ILA Course 01-02_LMK

7/31/2019 ILA Course 01-02_LMK

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Fundamentals of Optical Properties of

Nanostructured Materials and their

Growth.

L. M. Kukreja

Thin Film Laboratory

Raja Ramanna Centre for Advanced Technology

P.O. CAT, Indore 452 013,

Email: [email protected]


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Contents

1. Introduction

2. Fundamentals of Nanostructured Semiconductors

2.1 Energy states of carriers in free space of different dimensionality

2.2 Effect of confinement on carrier energy states

2.3 Density of states

2.3.1 Density of states for bulk materials

2.3.2 Density of states for two dimensional materials

2.3.3 Density of states for one dimensional materials

2.3.4 Density of states for zero dimensional materials

2.4 Applications of Nanostructured Semiconductors

2.5 Reference on growth methodologies

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1. Introduction

Later part of the twentieth century witnessed a spectacular turn in the way we understood

material science. Earlier notion that to change material characteristics we need to change its

chemical composition or we need to mix materials in different modes or conditions remained no

more isolated. A radically different approach to understand materials emerged which converged

to the finding that material characteristics could now also be changed by changing the size

keeping the chemical composition intact [1-10]. However the methodology of varying the

material characteristics with size was feasible only in a specific size regime, called the quantum

confinement regime and the variation in a specific material characteristic invariably affected the

other characteristics of the same material as well [11-23]. However despite these limitations this

possibility to tailor the material properties by varying the size alone provided the mankind a

revolutionary wisdom of materials science, which enabled the emergence of a new branch of

technology called Nanotechnology. The fundamental drive to scale the height of Nanotechnology

to the extent that we witness today was not only to make more compact, denser and more

integrated devices but also because newer characteristics of the materials were discovered. These

characteristics offered the possibilities to push the existing frontiers of the technology in leaps.

Today Nanoscience and Nanotechnology are not only highly developed arenas of human

endeavors but also some of the fastest growing branches of science and technology [24-36] with

ramifications into multitude of areas such as Nano-medicine [24-29,37-41], Nanostructured

Semiconductor lasers [30,42-62], Solar Energy [63-72], Nano-electronics and Devices [73-90]

and Quantum Computations [91-94] etc.

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Why do Nanostructured materials behave differently? As we know that the genesis of most

material properties such as optical, magnetic, mechanical and chemical lies in the states of

electrons in the constituting atoms, their configuration in the atomic structures and the way these

electrons form bonds with the neighboring atoms in a molecular system. These electrons

experience confinement effects when those are trapped in a nanometer sized structure of the

material. It is thanks to these confinement effects that the material characteristics are unusual

and generally size dependent. Our current understanding on the wave nature of the microphysical

particles such as electrons and the quantum mechanics provide a fundamental basis for

explaining the confinement effects. Since the typical de Broglie wavelength of electrons is in

the range on nanometers, the confinement effects are pronounced and observable when the

confining system is of the comparable size. Another equally important is the ratio of surface area

to the volume of a material structure, which tends to increase when the particle size is decreased.

As a result the surface area dependent material properties start dominating or anomalous

behaviors are observed in the nano-scale regime. For example, nano-particle catalysts are found

to be chemically more effective than the bulk catalysts. Similarly, electric field related effects are

also enhanced in the nano-particles due to their sheer small size. For example, metal nano-

particle X-ray targets have been found to produce harder X-rays with enhanced yields [95, 96].

One of the most significant aspects of any technology is to fabricate materials compatible to that

technology. This aspect is rather demanding so for as the Nanotechnology is concerned. This is

because fabricating material structures of nanometer size with comprehensive control is an

intricate problem. However a host of methodologies have indeed been evolved to grow

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nanometer size structures of different materials under variety of conditions with varying degrees

of controls on shapes, structural qualities and sizes. In fact Nanofabrication is a gargantuan and

contemporary field of research and technology development. But in this chapter, to provide

reasonably thorough and deep knowledge, we will confine ourselves to a narrow slice of this

field, which deals with the nanofabrication of semiconductors using a very specific methodology

of Pulsed Laser Deposition (PLD).

To make the chapter self contained we have discussed in brief the fundamentals of

Nanostructured semiconductors specifically those pertinent to the confinement effects,

dimensions of confinement, dependence of band-gap on the confinement size and the density of

states. Since PLD is the basic methodology of nanofabrication discussed in this chapter, it has

been dealt with in detail. In this chapter we have exhaustively presented all the fundamental

aspects, the available level of technology, its merits and demerits and a perspective of the

existing trends of this versatile and still esoteric fabrication methodology for semiconductors.

Finally we have presented a digest of the state of affairs of the nanostructured semiconductors

grown by PLD. Some of the novel optical, structural, electrical and magnetic properties of these

PLD grown nanostructured semiconductors are also presented and discussed in this chapter

upholding its brevity.

2. Fundamentals of Nanostructured Semiconductors

A large number of books [1-10], review articles [24-36], and research papers [11-23,37-150]

have been published on the subject of nanostructured semiconductors and related materials. Most

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of the reported papers are devoted to confinement effect [11-23], applications in the area of

biotechnology, lasers, electronic devices and solar energy [37-96]. Some of these papers are also

devoted to growth and characterization of nanostructured semiconductor [97-150]. A

semiconductor structure having at least one dimension in the range of 1 to few hundred

nanometers is defined as a nanostructured semiconductor. Semiconductor structure with reduced

dimensionality has, amongst others, optical properties that are quite different from the optical

properties of crystalline bulk matter. For example, silicon has a band gap of about 1.2 eV in the

bulk crystalline state whereas nanocrystalline dots of silicon have band gaps of 2ev or more.

Thus semiconductor nanostructure shows size dependent properties different from those of a

macroscopic semiconductor if one or more dimensions of the structure are comparable to

wavelength of light or wavelength of electrons and holes. The quantum effects arise in systems,

which confine electrons to regions comparable to their de Broglie wavelength. In other words if

the physical size of a material structure becomes smaller, the quantum mechanical effects

become observable. In the following sections we will discuss the confinement effect and its

implications on allowed energy bands and densities of sates.

2.1 Energy states of carriers in free space of different dimensionality

In a nanostructured semiconductor, the quantum confinement occurs when electrons or holes in

the material are trapped in one or more of the three dimensions within nanometer size regime. If

the confinement occurs in one dimension only (say in the z-direction), it is assumed that the

carriers like electrons and holes have free motion in other two x and y directions. This

assumption is valid because size of the material in x and y directions is very large compared to

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the size in z-direction. Such a structure would be two dimensional and the carriers confined in

one dimension will have two degrees of freedom. If the confinement is in two directions (say y

and z), the electrons have free motion in x-direction. Such a structure would be one dimensional

and the carriers confined in two dimensions will have only one degree of freedom. Confinement

in all the three directions (i.e. x, y and z) will result in no free motion of electrons or holes in any

direction. Such a structure would be zero dimensional and the carriers confined in all the three

dimensions will have no degree of freedom. The inherent size dependent properties of these

Nanostructured materials will be result of two basic mechanisms: free energy variation due to

free motion of carrier like electron and quantized energies due to quantum confinement. The

total energy of electrons (or holes) will be the sum of allowed energies associated with the

motion of these carriers along the confined direction and the kinetic energy due to free motion in

the remaining unconfined directions. Let us first consider the energy of electrons due to free

unconfined motion.

In the case of bulk material an electron can be treated as unconfined. Therefore the following

Schrdinger equation for unconfined electron in free space can be used [2, 3]

=

+

+

E

zyxm 2

2

2

2

2

22

2

h (1)

Where m is the mass of the electron and E represents the allowed energy of such an

electron. The solution of this equation gives:

( )( )

( rikrk

.exp2

13

= ) (2)

Which are plane waves having wave vector kwith its components kx, kyand kzalong the

x, y and z directions respectively and can thus be represented as:

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( zyx kkkk ,,= ) (3)

Solution of equation (1) gives the kinetic energy E, which can be written as:

(222

222

22zyx kkkmm

kE ++==

hh

) (4)

For confinement in one dimension (say z), free motion of an electron is allowed only in two

dimension (x and y directions). The kinetic energy of an electron in two directions (x and y) can

be written as:

( 22222

22yx kk

mm

kE +==

hh ) (5)

For confinement in two dimensions (say z and y directions), the free motion of an electron is

allowed only in one direction (x direction). Therefore the kinetic energy of an electron due to

free motion in x-direction can be written as

m

k

m

kE x

22

2222hh

== (6)

So far we considered the kinetic energy of the electrons with different degrees of freedom. But

what happens to the energy states due to confinement? To understand this we need to solve the

Schrdinger equation in a potential well created by the confinement instead of the free space

case dealt with here. For the sake of comprehending the fundamentals concisely we will consider

an ideal square potential well, in different dimensions. For the confinement along one dimension,

it is the case of a quantum well, for confinement in two dimensions, it is quantum wire and

finally for the confinement in all the three dimensions it is the case of a quantum dot.

2.2 Effects of confinement on energy states

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A confined material structure is the one, which has one or more of its dimensions reduced to the

size of confinement regime i.e. in the range of nanometers. For example a semiconductor

quantum well is a two dimensional structure, which in practice consists of a low band gap

semiconductor confinement layer flanked by two layers of a higher band gap semiconductor on

either side. These layers are called the barrier layers and are invariably thicker than the

confinement layer, which is of thickness in the nanometer regime. Although such a structure has

finite depth of the potential well equal to the difference of the band gaps of the confinement and

the barrier layers, but for a theoretical understanding we can take the square potential well of

infinite depth. A schematic of such an infinite square well is illustrated in figure 1, where a is

the width of the well, which is equal to the thickness of the confinement layer. Now we will see

what happens to the electrons, which are confined in one direction in such a well.

V =

0 a

VZ a

V

Z

V= V=

V V = VZ a

0

0

0

V

Figure 1. One-dimensional infinite square potential well.

The electrons will have zero potential in the region < z


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An electron within this quantum well behaves as a free particle and its time independent

Schrdinger equation can be written as:

( )( )zE

z

z

m=

2

22

2

hfor az


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0 a

Energ

y(E)

Distance (Z)

n z = 1

nz = 2

Figure 2. Quantized energy levels for n = 1 and n = 2 and the corresponding wave functions for

infinite square potential well.

From equations (5) and (12) we can write total energy of the electron which is the sum of

quantized energy (in confined direction z) and the kinetic energy due to its (x, y) motion (in

unconfined directions). Thus the total energy of electronETotalis

( )222

2yxzTotal kk

mEnE ++=

h

or, by substituting for Enzfrom equation (12)

( 22222

22yx

zTotal kk

ma

n

mE ++

=

hh ) (13)

From this equation one can draw two inferences. One, the energy states are now quantized due to

the presence of the integers nz and second, the energy states are now size i.e. a dependent.

Thus quantum confinement results in the discreteness of the energy levels, which are now

dependent on the size of the confinement dimension.

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In similar way we can calculate the quantized energies and total energy for a quantum wire and a

quantum dot. In case of quantum wire two dimensions (say z and y) are confined, therefore total

energy for quantum wire can be written as

( )22

2xyzTotal k

mEnEnE

h++=

Or, by substituting for Enz,

( 22

2222

222x

yzTotal k

mb

n

ma

n

mE

hhh+

+

=

) (14)

The total energy for a quantum dot having all three dimensions (z, y and x) confined can be

written as

222

222

222

+

+

=

c

n

mb

n

ma

n

mE x

yzTotal

hhh(15)

Where are integers and are the confined sizes of material in z, y and x directions

respectively. From equations (14) and (15) it is clear that as the dimensions of confinement

increase the free space terms are replaced by the confinement terms in the energy states, which in

turn enhance the size dependence of the energy states. A similar size dependence of the energy

states can also be expected for holes in the valance band.

xyz nnn ,, cba ,,

2.3 Density of states

The density of states is defined as the number of energy states present in a unit energy interval

per unit volume of the material structure. The density of states gives an idea of the energies when

we combine the effect of confinement in one direction and unconfined in the remaining

directions. Now we will derive analytical expressions of density of states and see its effect on the

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electronic structure for bulk semiconductors (unconfined in all direction) and semiconductors

having confinement in one direction, two and three directions.

2.3.1 Density of states for bulk materials

One would like to know that how density of states depends on sizes of material in x, y and z

direction? For this let us consider the material having sizes in x, y and z directions

respectively as shown in figure 3. Let k be the wave vectors along x, y, z directions

respectively in k space.

zyx LLL ,,

zyx kk ,,

X

Y

Z

L Y

L X

L Z

Figure 3. Bulk material showing extension along all the three dimensions.

Under periodic boundary condition, the allowed values of wave vector along x, y and z

directions are

x

xL

k2

= (16a)

y

yL

k2

= (16b)

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z

zL

k2

= (16c)

The volume of a sphere of radius kin k space is given by

3*

3

4k=V (17)

Let n be the number of states/modes in the sphere, then

zyx kkk

Vn

*

=

or, zyx LLLk

n2

3

6= [Using equations (16a, b and c) and(17)]

When we consider the spins of electron, the total number of states in the sphere (say n ) can be

written as

=2n=n zyx LLLk

2

3

3(18)

Let be the number of states per unit volume of the bulk material. ThereforeVN3

=VN3zyx LLL

n = 2

3

3k (19)

The density of states for a three dimensional material defined asDN3E

NV

3 will therefore be,

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=DN3E

NV

3

From equation (19)

=DN3Ek

3

231

Or =DN3E

k

k

k

3

23

1

Or =DN3E

kk

2

2

(20)

But from equation (4)2

2 2

h

mE=k for free electron. Therefore equation (20) can be written as:

=DN3E

EmmE

21

2

1

222

221

hh

Or =DN3 Em 2

3

22

2

2

1

h(21)

This gives the density of states in three dimensions. It is obvious from this equation that

DN3 E (22)

This dependence of density of states for three dimensions is shown in figure 4.

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Density ofstates

Energy (E)

(N3D)

Figure 4. Variation of density of states with energy for bulk material i.e. a three dimensional

semiconductor.

2.3.2 Density of states for two dimensional materials

Now let us consider the density of states in a material structure having confinement in one

direction (say z) such as a quantum well. Earlier it was mentioned that the total energy of carriers

in such system is a sum of quantized energy along the quantized direction (Enz) plus the kinetic

energy of electron in other two free directions (Ex, y) i.e.

(23)yxzTotal EEnE ,+=

From equations (12) and (13), we can write

=TotalE ( 222

22

22yx

z

z kkmL

n

m++

hh ) (24)

Where Lz is the confinement width of the structure say the quantum well or width of

material in quantized direction and

n ......................3,2,1=z

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and k2=kx

2+ ky

2

For calculation of density of states in two dimensional materials we take area (A) instead of

volume (for the three dimensional case) in k space, which would be:

A= (25)2k

and the allowed values of wave vector along x and y directions would be:

kx=xL

2(26a)

ky=yL

2(26b)

The area of a given state/modes will be kx, ky.

Now let is the number of states in k space area. Thereforen

n =yxkk

A

Or using equation (25),

n =yxkk

k

2

(27)

From equations (26a and b) and (27), we can write

n =4

2

yxLLk

If we consider the spins of electron, the total number of states in area (let n ) can be written as:

n =2 =2 n4

2

yxLLk

Or =n2

2

yxLLk(28)

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Let is the number of states per unit area in real space of the two dimensional material, in

that case,

VN2

=VN2 yxLL

n

Therefore, using equation (28),

=VN22

2

yxLLk

yxLL

1

Or =VN22

2k(29)

Let be the density of states for two dimensional materials, which as per the above definition

is

DN2

E

N V

2 . Then,

=DN2E

N V

2 =

2

2k

E[From equation (29)]

Or =D

N2 E

k

2

2

1

Or =DN2E

k

k

k

2

2

1

Or =DN2E

kk

(30)

From the solution of Schrdinger equation for free electron motion as from equation (4), we

know that2

2 2hmEk = , therefore equation (30) reduces to

=DN22

1

2

2

1

2

221

hh

mE

E

mE

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Or

22h

mND = (31)

This shows that the density of states for a two dimensional structure is constant and does not

depend on the energy due to free motion of electron. It may be noted here that this is the energy

density of the sub-band for a given kz (orEnz). There will be an additional

2h

mterm for each

successive kzorEnz. Therefore the comprehensive density of states can be written as

(=

=...2,1

22

zn

zD EnEm

Nh

) (32)

Where

is a step function and,

when zEnE= , =1

and for zEnE , =0

A schematic dependence of density of states on energy for a two dimensional material structure

such as quantum well is shown in figure 5.

Density ofstates

Energy (E)

(N'2D)

Figure 5. Variation of density of states with energy for quantum wells i.e. a two dimensional

semiconductor.

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2.3.3 Density of states for one dimensional materials

The one dimensional material structure is defined as that which has two dimensions confined

(say z and y directions) and one dimension unconfined (say x direction). The total energy of the

system in this case can be written as

xyzTotal EEnEnE ++=

Or =TotalE ( 22

22

22

222

x

y

y

z

z k

mL

n

mL

n

m

hhh+

+

) (33)

Where Lz and Ly are widths of material in quantized directions and n are integers.yz n,

And k2= kx

2.

In k space total length will be 2k because we consider both positive and negative directions.

Therefore the number of states/modes ( n ) along this length is

xk

k2

=n

Or kLx

=

n (34)

where the allowed value of kx isxL

2

After considering the two spins of electrons, the number of states per unit length (let n ) can be

written as

kL

n x

==

22n

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when E=Enz,,ny , =1

and forE En z,ny, =0

The behavior of density of states for a one dimensional system is shown in figure 6.

Density ofstates

(N'1D)

Energy (E)

Figure 6. Variation of density of states with energy for quantum wire i.e. a one dimensional

semiconductor

2.3.4 Density of states for zero dimensional materials

A material having all dimensions confined (say z, y and x), is known as zero dimensional

material. In this case there are no dimensions in which free motion of charge carriers is possible.

The total energy of this system will be

xyzTotal EnEnEnE ++=

=TotalE

22

22

22

222

+

+

x

x

y

y

z

z

L

n

mL

n

mL

n

m

hhh(38)

Where are integers.xyz nnn ,,

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In this case there are no allowed values of wave vector along x, y, and z directions, therefore the

density of states can be written as

xyzD nnEnEN ,,0 = (39)

A schematic of the functional dependence of density of states on energy for a zero dimensional

system is shown in figure 7.

Density ofstates

Energy (E)

(N'0D)

Figure 7. Variations of density of states with energy for quantum doti.e. a zero dimensional

semiconductor.

2.4 Applications of Nanostructured Semiconductors

In the last decade nanostructured materials have attracted much attention from physicists,

chemists and engineers due to their intriguing electrical and optical properties, which are found

to be different from those of bulk materials. As seen above the electrical and optical properties of

nanostructured semiconductors are highly size dependent and thus can be modified by varying

the size alone, keeping the chemical composition in tact [1-23]. These size variations and

confinement dimensions only categorize the nanostructured materials as quantum wells, quantum

wires, and quantum dots. Even today Nanoscience and nanotechnology continue to be an active

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and challenging subject in material science and other fields. Nanostructured materials have

variety of applications in the areas of biotechnology and medicine [24-29, 37-41], semiconductor

quantum devices [73-90], solar cells [63-72], quantum computations [91-94], semiconductor

lasers [42-62] etc. To discuss all these applications in detail here is beyond the scope of this

chapter. Therefore we will touch upon some of the applications, especially that of nanostructured

semiconductors.

Fluorescence microscopy is one of the finest methods for biological research and has emerged as

an inescapable tool for cell biologists. It provides real-time imaging of living cells with high

resolution. But for fluorescence microscopy one needs Biological labeling. Conventionally

biological labeling is carried out by using organic dyes such as tetramethylrhodamine (TMR).

However the organic dyes have certain limitations such as sensitivity to pH changes,

susceptibility to photo bleaching, fixed fluorescence spectra and separated absorption and

fluorescence maxima etc. In recent years, semiconductor quantum dots have been applied

biological labeling, which overcome the above mentioned drawbacks [25]. It provides the option

of continuously tuning the emission wavelength of the semiconductor by changing the size of its

quantum dots. For example it is possible to tune the emission of quantum dots of CdSe over the

entire visible spectrum by changing the radius of its dots. Quantum dots have narrow emission

spectra (for example that of CdSe have a bandwidth of about 30nm) therefore a single light

source can be used for excitation of multiple semiconductor quantum dots to emit different

colors. Each of these different - colored quantum dots could be functionalized with a unique

ligand-biomolecule pair, which in turn facilitates binding it to a particular biological structure.

This makes multicolor experiments more convenient. In addition to this, semiconductor quantum

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dots are inorganic and more robust for photobleaching than organic dyes; it is also insensitive to

pH changes of the biological environments. These optical properties of semiconductor quantum

dots make them ideal biological labeling materials which have applications in bioengineering as

a well as in cell and molecular biology.

The applications and uses of semiconductor lasers are well known to scientific as well medical

communities and industries. Conventional sources of lasers use gases, organic dyes and

semiconductors etc. as their active mediums. The semiconductor lasers are widely used for

applications in compact disc players, laser printers etc. Those are also well known to play critical

and important role in optical communication, spectroscopic studies, defense and numerous

industries etc. In the case of nanostructured semiconductor lasers, the carrier confinement and

nature of electronic density of states of the nanostructures make it more efficient for devices

operating at lower threshold currents than lasers with bulk materials. The size dependent

emission spectra of quantum wells, quantum wires and quantum dots make them attractive lasing

media. The performance of quantum dot lasers is less temperature dependent than conventional

semiconductor lasers [45]. Due to size dependent emission of nanostructured semiconductors, in

principle, a single device can work for a blue, green or a red laser.

Nature has provided us abundant energy through sun light, which is commonly known as solar

energy. The physicists, chemists and engineers are trying to develop devices called Solar cell to

harness this energy with higher efficiencies. Due to size dependent optical and electrical

properties, the nanostructured materials can play an important role for increasing the efficiencies

of solar cell. The conventional solar cells are made by semiconductor material like silicon and

organic dyes or combination of both. But the efficiencies of these solar cells are in range of 15%

to 30%. Due to this lower efficiency, it requires large solar panel which increases the cost, size as

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well as the maintenance related problems. A wide gap semiconductor such as Zinc Oxide (ZnO)

grown in a nanostructured form is more efficient and convenient for photovoltaic applications as

a part of a solar cell [67]. The nanostructured surfaces coated with extremely thin absorber lead

to low optical losses and increases carrier transfer between active region and contact. The

semiconductor quantum dots have tunable size dependent absorption and emission characteristics

so it can be made to absorb the sunlight through out from UV to IR region. This is not possible

with organic dyes. The quantum dots are more photo-stable and the absorption cross section of

quantum dots is an order of magnitude higher than organic dyes. These properties make the

nanostructured semiconductors as ideal and efficient elements for solar cells. The nanostructured

thin film solar cells are more advantageous over the conventional solar cells because those have

less material utilization, enhanced efficiency and in some cases low processing costs etc [71].

In addition to the aforesaid applications, there are many other applications of nanostructured

semiconductors like light emitting diodes, quantum dots as memory elements, quantum

computation, sensors for toxic gases and chemicals, quantum well modulators, nano-scale

semiconductor quantum device for information and telecommunications and electroluminescent

devices etc [73-94]. It is possible to make small and efficient optical modulators using

semiconductor quantum wells [10, 88, and 89]. It is known that the optical absorption of the

quantum wells can be changed by applying an electric field perpendicular to its surface. Also in

case of quantum wells the change in absorption is relatively large which makes it suitable for

optical modulators. In the field of quantum information processing, using multi-color laser pulses

from a semiconductor quantum dot array, it is possible to perform single as well as two qubit

gate operations. By these means one can implement basic quantum computation operations on

time scale much shorter than the exciton dephasing time [93].

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References

P.Harrison, Quantum Wells, Wires and Dots, John Wiely, New York (2000)1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

15.

K. Barnham and D. Vvedensky (Eds), Low-Dimensional Semiconductor structures,

Cambridge University Press, Cambridge (2001)

J. H. Davies, The Physics of Low-Dimensional Semiconductors, Cambridge

University Press, Cambridge (1998)

C. Delerue and M. Lanno,Nanostructures, Springer, New Delhi (2004)

G. Schmid,Nanoparticles, Wiley-VCH, Weinheim (2004)

T. Numai,Fundamentals of Semiconductor Lasers, Springer, New York (2004)

V. V. Mitin, V. A. Kochelap and M. A. Stroscio, Quantum Heterostructures, Cambridge

University Press, Cambridge (1999)

A. Shik, Quantum Wells, World Scientific, Singapore (1999)

M. Jaros, Physics and Applications of Semiconductor Microstructures, Clarendon Press,

Oxford (1989)

D. A. B. Miller, D. S. Chemla and S. Schmitt-Rink in Electric Field Dependence of

Optical Properties of Semiconductor Quantum Wells, edited H. Haug, Academic Press,

Boston (1988)

E. M. Kazaryan, L. S. Petrosyan and H. A. Sarkisyan, Physica E, 16, 174 (2003)

M. S. Gudiksen, J. Wang, C. M. Liber, J. Phys. Chem. B, 106, 4036 (2002)

H. Ajiki, Journal of Luminescence, 94, 173 (2001)

Y. Li, O. Voskoboynikov, C. P. Lee and S. M. Sze, Solid State Communications,120, 79

(2001)

N. Fominykh and J. Berakdar, Surface Science, 482, 618 (2001)

27


28/37

G. Goldoni, F. Rossi, A. Orlandi, M. Rontani, F. Manghi and E. Molinari, Physica E, 6,

482 (2000)

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

29.

30.

31.

32.

C. Piermarocchi, R. Ambigapathy, D. Y. Oberli, E. Kapon, B. Deveaud and F. Tassone,

Solid State Communications, 112, 433 (1999)

W. Xie and C. Chen, Physica B, 266, 373 (1999)

S.Muto and A. Tackeuchi, Materials Science and Engineering, R22, 79 (1998)

X. Peng, J. Wickham and A. P. Alivisatos, J. Am. Chem. Soc. 120, 5343 (1998)

N. T. Dan and F. Bechstedt, Physica B, 219, 47 (1996)

M. F. Crommie, C. P. Lutz, D. M. Eigler, Science, 262, 218 (1993)

E. Kapon, D. M. Hwang, M. Walther, R. Bhat and N. G. Stoffel, Surface Science, 267,

593 (1992)

G. A. Hughes, Nanomedicine: Nanotechnology, Biology and Medicine, 1, 22 (2005)

D. Alexson, H. Chen, M. Cho, M. Dutta, Y. Li, P. Shi, A. Raichura, D. Ramadurai, S.

Parikh, M. A. Stroscio and M. Vasudev, J. Phys.: Condens. Matter, 17, 637 (2005)

W. Jiang, E. Papa, H. Fischer, S. Mardyani and W. C. W. Chan,Trends in Biotechnology,

22, 607 (2004)

R. E. Bailey, A. M. Smith and S. Nie, Physica E, 25, 1 (2004)

J. Wang, Analytical Chimica Acta, 500, 247 (2003)

W. C. W. Chan, D. J. Maxwell, X. Gao, R. E. Bailey, M. Han and S. Nie, Current

Opinion in Biotechnology, 13, 40 (2002)

M. Grundmann, Physica E, 5, 167 (1999)

S. S. Li, Materials Chemistry and Physics, 50, 188 (1997)

G. Platero and R. Aguado, Physics Reports, 395, 1 (2004)

28


29/37

K. Jacobi, Progress in Surface Science, 71, 185 (2003)33.

34.

35.

36.

37.

38.

39.

40.

41.

42.

43.

44.

45.

46.

47.

C. Teichert, Physics Reports, 365, 335 (2002)

P. G. Eliseev, Progress in Quantum Electronics, 20, 1 (1996)

A. Fuhrer, A. Dorn, S. Luscher, T. Heinzel, K. Ensslin, W. Wegscheider and M. Bichler,

Superlattices and Microstructures, 31, 19 (2002)

Y. Wang, Z. Tang and N. A. Kotov, Materials Today, 8, 20 (2005)

L. C. Mattheakis, J. M. Dias, Y.J. Choi, J. Gong, M. P. Bruchez, J. Liu and E. Wang,

Analytical Biochemistry, 327, 200 (2004)

A.Hoshino, K.Hanaki, K. Suzuki and K. Yamamoto, Biochemical and Biophysical

Research Communications, 314, 46 (2004)

Y. Cui, Q. Wei, H. Park and C. M. Lieber, Science, 293, 1289 (2001)

M. Bruchez Jr, M.Moronne, P. Gin, S. Weiss and A. P. Alivisatos, Science, 281, 2013

(1998)

D. Bimberg, M. Grundmann, F. Heinrichsdorff, N. N. Ledentsov, V. M. Ustinov, A. E.

Zhukov, A. R. Kovsh, M. V. Maximov, Y. M. Shernyakov and B. V. Volovik, Thin Solid

Films, 367, 235 (2000)

S. Iwamoto, J. Tatebayashi, S. Kako, S. Ishida and Y. Arkawa, Physica E, 21, 814 (2004)

S. Lu, R. Jia, D. Jiang and S. Li, Physica E, 17, 453 (2003)

L. V. Asryan and S. Luryi, Solid-State Electronics, 47, 205 (2003)

M. Kamp, M. Schmitt, J. Hofmann, F. Schafer, J. P. Reithmaier and A. Forchel, Electron.

Lett. 35, 2036 (1999)

C. Gmachl, A. Tredicucci, D. L. Sivco, A. L. Hutchinson, F. Capasso and A. Y. Cho,

Science, 286, 749 (1999)

29


30/37

A. Tredicucci, C. Gmachl, F. Capasso, D. L. Sivco, A. L. Hutchinson and A. Y. Cho,

Nature, 396, 350 (1998)

48.

49.

50.

51.

52.

53.

54.

55.

56.

57.

58.

59.

60.

61.

S.M. Wang, Y.Q. Wei, X.D. Wang, Q.X. Zhao, M. Sadeghi and A. Larsson, Journal of

Crystal Growth, 278, 734 (2005)

L. R. Ram-Mohan, I. Vurgaftman and J. R. Meyer, Microelectronics Journal, 30, 1031

(1999)

V. K. Kononenko, I. S. Manak and S. V. Nalivko, Spectrochimica Acta Part A:

Molecular and Biomolecular Spectroscopy, 55, 2091 (1999)

S. Simanowski, M. Walther, J. Schmitz, R. Kiefer, N. Herres, F. Fuchs, M. Maier, C.

Mermelstein, J. Wagner and G. Weimann, Journal of Crystal Growth, 201, 849 (1999)

T. J. Bukowski and J. H. Simmons, Critical Reviews in Solid State and Material

Sciences, 27, 119 (2002)

S. Charbonneau, P. J. Poole, P. G. Piva, M. Buchanan, R. D. Goldberg and I. V. Mitchell,

Nuclear Instruments and Methods in Physics Research Section B, 106, 457 (1995)

W. H. Seo and B. H. Han,Solid State Communications,119, 367 (2001)

T. G. Kim, X. L. Wang, R. Kaji and M. Ogura, Physica E, 7, 508 (2000)

L. Sirigu, L. Degiorgi, D. Y. Oberli, A. Rudra and E. Kapon, Physica E, 7, 513 (2000)

P. J. Pearah, A. C. Chen, A. M. Moy, K. C. Hsieh and K. Y. Cheng, Journal of Crystal

Growth, 150, 293 (1995)

M. Asada, Y. Miyamoto, Y. Suematsu, IEEE J. Quantum Electron., 22, 1915 (1986)

F. Klopf, J. P. Reithmaier, A. Forchel, Appl. Phys. Lett. 77, 1419 (2000)

R. Krebs, F. Klopf, J. P. Reithmaier, A. Forchel, Japan J. Appl. Phys. 41, 1158 (2002)

30


31/37

R. Schwertberger, D. Gold, J. P. Reithmaier, A. Forchel, IEEE Photon. Technol. Lett. 14,

735 (2002)

62.

63.

64.

65.

66.

67.

68.

69.

70.

71.

72.

73.

74.

75.

76.

A. J. Nozik, Physica E. 12, 115 (2002)

R. P. Raffaelle, S. L. Castro, A. F. Hepp and S. G. Bailey, Progress in photovoltaics:

research and applications, 10, 433 (2002)

B. Das, S. P. McGinnis and P. Sines, Solar Energy Materials and Solar Cells, 63, 117

(2000)

B. R. Mehta and F. E. Kruis, Solar Energy Materials and Solar Cells, 85, 107 (2005)

J. Cembrero, A. Elmanouni, B. Hartiti, M. Mollar and B. Mar, Thin Solid Films, 451,

198 (2004)

C. L. Clment, A. Katty, S. Bastide, F. Zenia, I. Mora and V. M. Sanjose, Physica E, 14,

229 (2002)

C. Grasso, M. Nanu, A. Goossens and M. Burgelman, Thin Solid Films, 480, 87 (2005)

D. Menzies, Q. Dai, Y. B. Cheng, G.P. Simon and L. Spiccia, Materials Letters, 59, 1893

(2005)

P.J. Sebastian and S.A. Gamboa, Solar Energy Materials and Solar Cells, 88, 129 (2005)

M. H. Wu, R. Mu, A. Ueda, D.O. Henderson and B. Vlahovic, Materials Science and

Engineering B, 116, 273 (2005)

B. Das and P. Singaraju, Infrared Physics& Technology, 46, 209 (2005)

R. Kucharczyk, L. Dobrzynski, B. D.Rouhani and A. Akjouj, Physica E, 24, 355 (2004)

X. Duan, Y. Huang, Y. Cui, J. Wang and C. M. Lieber, Nature, 409, 66 (2001)

Y. Cui and C. M. Lieber, Science, 291, 851 (2001)

31


32/37

F. Fossard, F. H. Julien, E. Peronne, A. Alexandrou, J. Brault and M. Gendry, Infrared

Physics& technology, 42, 443 (2001)

77.

78.

79.

80.

81.

82.

83.

84.

85.

86.

87.

88.

89.

90.

91.

92.

A. Backtold, P. Hadley, T. Nakanishi and C. Dekker, Science, 294, 1317 (2001)

D. Bimberg, F. Heinrichsdorff, N. N. Ledentsov and V. A. Shchukin, Applied Surface

Science, 159, 1 (2000)

E. H. Lee and K. Park, Materials Science and Engineering B, 74, 1 (2000)

H. Luth, Applied Surface Science, 130, 855 (1998)

D. L. Klein, R. Roth, A. L. L. Lim, A. P. Alivisatos and P. L. McEuen, Nature, 389, 699

(1997)

G. Ma and X. Dai, Physica C, 282, 2509 (1997)

E. Nakayama, K. Kayanuma, T. Tomita, A. Murayama, Z. H. Chen and Y. Oka, Physica

E, 21, 1027 (2004)

V. M. Agranovich, D. M. Basko, G. C. La Rocca and F. Bassani, Synthetic Metals, 116,

349(2001)

O. K. Tan, W. Cao, Y. Hu and W. Zhu,Solid State Ionics, 172, 309 (2004)

I. R.Philip, E. Moreau, S. Varoutsis, J. Bylander, M. Gallart, J. M. Grard and I. Abram,

Journal of Luminescence, 102, 67 (2003)

D. A. B. Miller, International Journal of High Speed Electronics, 1, 19 (1990)

A. L. Lentine and D. A. B. Miller, IEEE J. Quantum Electronics, 29, 655 (1993)

T. Rupp, J. Messarosch and I. Eisele, Journal of Crystal Growth, 183, 99 (1998)

M. Feng, Physics Letters A, 306, 353 (2003)

P. Zanardi, I. DAmico, R. Ionicioiu, E. Pazy, E. Biolatti. R. C. Iotti and F. Rossi,

Physica B, 314, 1 (2002)

32


33/37

93.

94.

95.

96.

97.

98.

99.

I. D'Amico, E. Biolatti, E. Pazy, P. Zanardi and F. Rossi, Physica E, 13, 620 (2002)

O.Gywat, G. Burkard and D. Loss, Superlattices and Microstructures, 31, 127 (2002)

P. P. Rajeev, P. Taneja, P. Ayyub, A. S. Sandhu and G. R. Kumar, Phys. Rev. Lett. 90,

115002 (2003)

P. P. Rajeev, P. Ayyub, S. Bagchi and G. R. Kumar, Optics Letters, 29, 2662 (2004)

I. Essaoudi, B. Stb, A. Ainane and M. Saber, Physica E, 14, 336 (2002)

B. S. Monozon and P. Schmelcher, Superlattices and Microstructures, 26, 229 (1999)

R. Ntzel, Q Gong, M. Ramsteiner, U. Jahn, K. J. Friedland and K. H. Ploog,

Microelectronics Journal, 33, 573 (2002)

100. J. Rubio, C. Pascual, A. Pinczuk, B. S. Dennis, L. N. Pfeiffer, K. W. West and J. M.

Calleja, Physica E, 12, 722 (2002)

101. R. Ntzel and K. H. Ploog, Journal of Crystal Growth, 227, 8 (2001)

102.H. Ikada, T. Saito, N. Takahashi, K. Shibata, T. Sato, Z. Chen, I. Souma and Y. Oka,

Physica E, 10, 373 (2001)

103. F. Lelarge, T. Otterburg, D. Y. Oberli, A. Rudra and E. Kapon, Journal of Crystal

Growth, 221, 551 (2000)

104. K. H. Ploog and R. Ntzel, Thin Solid Films, 367, 32 (2000)

105. F. Vouilloz, D. Y. Oberli, F. Lelarge, B. Dwir and E. Kapon, Solid State

Communications, 108, 945 (1998)

106. G. A. Narvaez, M. C. de O. Aguiar and J. A Brum, Physica E, 2, 983 (1998)

107. L. Tapfer, L. De Caro, Y. Zhuang, P. Sciacovelli and A. Sacchetti, Thin Solid Films,

319, 49 (1998)

108. A. Balandin and S. Bandyopadhyay, Superlattices and Microstructures, 19, 97 (1996)

33


34/37

109. J. M. Calleja, A. R. Goi, B. S. Dennis, J. S. Weiner, A. Pinczuk, S. Schmitt-Rink, L. N.

Pfeiffer, K. W. West, J. F. Mller and A. E. Ruckenstein, Surface Science, 263, 346

(1992)

110. R. Ntzel, L. Dweritz and K. Ploog, Journal of Crystal Growth, 115, 318 (1991)

111. A. Delgado, A. Gonzalez and D.J. Lockwood, Solid State Communications, 135, 554

(2005)

112. I. Lyubinetsky, A.S. Lea, S. Thevuthasan and D.R. Baer, Surface Science, 589, 120

(2005)

113. J. L. Primus, K. H. Choi, A. Trampert, A. M. Yakunin, J. Ferr, J. H. Wolter, W. V.Roy

and J. D. Boeck, Journal of Crystal Growth,280, 32 (2005)

114. M.D. Robertson, J.C. Bennett, A.M. Webb, J.M. Corbett, S. Raymond and P.J. Poole,

Ultramicroscopy, 103, 205 (2005)

115. T.O. Cheche and M.C. Chang, Chemical Physics Letters,406, 479 (2005)

116. G. Bacher, H. Schmig, M. Scheibner, A. Forchel, A. A. Maksimov, A.V. Chernenko,

P.S. Dorozhkin, V. D. Kulakovskii, T. Kennedy and T. L. Reinecke, Physica E, 26, 37

(2005)

117. E. Rodriguez, E. Jimenez, G.J. Jacob, A. A. R. Neves, C. L. Cesar and L. C. Barbosa,

Physica E, 26, 361 (2005)

118. J. H. Kratzer and J. Schroeder, Journal of Non-Crystalline Solids, 349, 299 (2004)

119. A. G. Steffan and R. T. Phillips, Physica E, 17, 15 (2003)

120. G. N. Panin, T. W. Kang, T. W. Kim, S. H. Park, S. M. Si, Y. S. Ryu and H. C. Jeon,

Physica E, 17, 484 (2003)

121. P. Koskinen and U. Hohenester, Solid State Communications, 125, 529 (2003)

34


35/37

122. A.C.C. Esteves and T. Trindade, Current Opinion in Solid State and Materials Science,

6, 347 (2002)

123. P. Sen and J. T. Andrews, Solid State Communications, 120, 195 (2001)

124. G. Li, J. Zhang, L. Yang, Y. Zhang and L. Zhang, Scripta Materialia, 44, 1945 (2001)

125. P. Chen, C. Piermarocchi and L. J. Sham, Physica E, 10, 7 (2001)

126. C. D. Simserides, U. Hohenester, G. Goldoni and E. Molinari, Materials Science and

Engineering B, 80, 266 (2001)

127. B. Vohnsen, S. I. Bozhevolnyi, K. Pedersen, J. Erland, J. R. Jensen and J. M. Hvam,

Optics Communications, 189, 305 (2001)

128. S. Facsko, T. Dekorsy, C. Trappe and H. Kurz, Microelectronic Engineering, 53, 245

(2000)

129. S. V. Nair and Y. Masumoto, Journal of Luminescence,87, 438 (2000)

130. J. Valenta, J. Dian, P. Gilliot and R. Lvy, Journal of Luminescence,86, 341 (2000)

131. A. A. Lipovskii, E. V. Kolobkova, A. Olkhovets, V. D. Petrikov and F. Wise, Physica E,

5, 157 (1999)

132. J. T. Andrews and P. Sen, Superlattices and Microstructures,26, 171 (1999)

133. J. See, P. Dollfus, S. Galdin and P. Hesto, Physica E, 21, 496 (2004)

134. X. L. Gou, J. Chen and P.W. Shen, Materials Chemistry and Physics, 93, 557 (2005)

135. S. Kapoor and P. K. Sen, Superlattices and Microstructures, 32, 117 (2002)

136. G. Sek, K. Ryczko, J. Misiewicz, M. Fischer, M. Reinhardt and A. Forchel, Thin Solid

Films,380, 240 (2000)

137. M. Ohe, M. Matsuo, T. Nogami, K. Fujiwara and H. Okamoto, Microelectronic

Engineering, 51, 135 (2000)

35


36/37

138. A. Neogi, H. Yoshida, T. Mozume and O. Wada, Optics Communications, 159, 225

(1999)

139. M. C. Y. Chan, E. H. Li and K. S. Chan, Physica B: Condensed Matter, 245, 317 (1998)

140. M. Koch, G. von Plessen, J. Feldman and E. O. Gbel, Chemical Physics, 210, 367

(1996)

141. R. P. M. Krishna and A.Chatterjee, Physica B, 358, 191 (2005)

142. F. Qu and P. C. Morais, Physics Letters A, 310, 460 (2003)

143. R. S. D. Bella and K. Navaneethakrishnan, Solid State Communications, 130, 773

(2004)

144. V. Dneprovskii, E. Zhukov, V. Karavanskii, V. Poborchii and I. Salamatina,

Superlattices and Microstructures, 23, 1217 (1998)

145. S. A. Hassan, A. R. Vasconcellos and R. Luzzi, Solid State Communications, 106, 253

(1998)

146. S. Ossicini, C. M. Bertoni, M. Biagini, A. Lugli, G. Roma and O. Bisi, Thin Solid Films,

297, 154 (1997)

147. R. Ferreira, O. Verzelen and G. Bastard, Physica E, 21, 164 (2004)

148. P. Nandakumar, C. Vijayan and Y.V.G. S. Murti, Optics Communications, 185, 457

(2000)

149. N. Q. Huong and J. L. Birman, Journal of Luminescence, 87, 333 (2000)

150.B. Szafran, J. Adamowski and S. Bednarek, Physica E, 5, 185 (1999)

36


37/37

1.

2.5 Reference on growth methodologiesNanotechnology

edited by Gregory Timp

Publ: AIP Press / Springer, New York (1999)

2. Physics of semiconductor nanostructuresedited by K P JainPubl: Narosa Publishing House, New Delhi (1997)

3. Semiconductor nanocrystals: from basic principles to applicationsedited by Alexander L. Efros, David J. Lockwood, and Leonid Tsybeskov.

Kluwer Academic / Plenum Publishers, New York (2003)

4. Nanotechnology and nanoelectronics: materials, devices, measurement techniques

W.R. Fahrner (editor).Publ.: Springer, Berlin (c2005)

5.

6.

7.

Low-dimensional semiconductor structures: fundamentals and device applicationsedited by Keith Barnham and Dimitri Vvedensky.Publ: Cambridge University Press, Cambridge (2001)

Nanolithography: a borderland between STM, EB, IB, and x-

ray lithographies, proceedings of the NATO advanced research workshop ...,

Frascati, Roma, Italy, April 6-8, 1993edited by M Gentili, C Giovannella and S Selci

Publ: Kluwer Academic Publishers, Dordrecht (1994)

Pulsed laser deposition of thin filmsedited Douglas B. Chrisey and Graham K. Hubler

John Wiley & Sons Inc., New York (1994)

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