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Applied Surface Science 288 (2014) 166– 171

Contents lists available at ScienceDirect

Applied Surface Science

jou rn al h omepa g e: www.elsev ier .com/ locate /apsusc

he effect of substrate temperature on structural and morphologicalroperties of Au/Si(1 1 1) thin films

aniel Marconia,∗, Alia Ungureana,b

Department of Molecular and Biomolecular Physics, National Institute for Research and Development of Isotopic and Molecular Technologies, Donath3-105, 400293 Cluj-Napoca, RomaniaFaculty of Physics, Babes -Bolyai University, Kogalniceanu 1, 400084 Cluj-Napoca, Romania

r t i c l e i n f o

rticle history:eceived 27 June 2013eceived in revised form1 September 2013ccepted 1 October 2013

a b s t r a c t

We report here the effects of substrate temperature on the orientation and surface morphology of 100 nmthick gold films, using scanning tunneling microscopy and X-ray diffraction. The gold films were depositedusing molecular beam epitaxy technique onto Si(1 1 1) 7 × 7 substrates. Ex situ characterizations areperformed using scanning tunneling microscope at room temperature. X-ray diffraction measurementsreveal the (1 1 1) orientation of the film deposited at 580 ◦C. We present data showing the evolution of

vailable online 9 October 2013

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the RMS roughness amplitude of the gold films as a function of substrate temperature during deposition.For our purposes, the best compromise between roughness and grain size is found to occur for a substratetemperature maintained at 580 ◦C.

© 2013 Elsevier B.V. All rights reserved.

. Introduction

Thin film deposition technology is in a continuous growingnd development, due to the high demand of new productsnd devices in the electronics and optical industries [1]. Manyunctional systems incorporate thin film devices like light emittingiodes, field effect transistors, nonlinear optical materials, recti-ying junctions or photovoltaic devices. An increasing interest isoward thin-film nanostructures [2] and their present use in nanond microelectronics. There are numerous ways to deposit thinlms on different substrates with various thicknesses, dependingn the desired application. One of these methods is moleculaream epitaxy (MBE). The term “epitaxy” describes an ordered,rystalline structure of the deposited film, with respect to that ofhe underlying substrate [3,4]. This method uses localized beamsf atoms or molecules in an ultra-high vacuum (UHV) environmento provide a source of the constituents to the growing surface of

substrate crystal [3]. Numerous methods can be used to char-cterize the deposited layer, like reflection high energy electron

iffraction (RHEED), low energy electron diffraction (LEED),ransmission electron microscopy (TEM), scanning probe

icroscopy (SPM) techniques or ellipsometry.

∗ Corresponding author. Tel.: +40 264584037; fax: +40 264420042.E-mail address: daniel.marconi@itim-cj.ro (D. Marconi).

169-4332/$ – see front matter © 2013 Elsevier B.V. All rights reserved.ttp://dx.doi.org/10.1016/j.apsusc.2013.10.001

A comprehensive grammar of epitaxy with fundamentalconcepts description, including the energetic considerations is pre-sented elsewhere [5].

Different materials are used as substrates for epitaxial depo-sition. Among these, silicon is a good candidate for growing thinfilms used in advanced devices, due to several important fac-tors: the possibility to be thermally oxidized to produce a stable,insulator oxide (SiO2); the low surface state density at the silicon-oxide interface to ensure reproducibility; large-scale integrationdue to the planner structure [6]. Si(1 1 1) substrates are known todevelop the 7 × 7 reconstruction, an attempt of the surface atomsto reduce the surface free energy. This is possible only in the caseof clean surfaces in ultra-high vacuum (UHV) conditions. A com-monly accepted model to describe the atomic arrangement of theSi(1 1 1)- 7 × 7 reconstructed surface is the dimer adatom-stacking(DAS) fault model [7]. This model consists of 12 adatoms and 6rest atoms, which are evenly distributed in the faulted half unitcell (FHUC) and unfaulted half unit cell (UHUC). The large unitcell size (2.7 nm × 2.7 nm) makes this surface an ideal templatefor the growth of well-ordered nanostructures [8]. It contains 19dangling bonds perpendicular to the surface, 12 for the adatoms,6 for the rest atoms and 1 for the corner atom below the vacancy.

The atomic scale resolution images of Si(1 1 1) 7 × 7 reconstruc-tion were obtained by using techniques as scanning tunnelingmicroscopy (STM), atomic scale microscopy [9] and atomic forcemicroscopy [10,11].

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D. Marconi, A. Ungurean / Applie

Various metals can be deposited using MBE technique. Of par-icular interest is gold (Au), due to the large domain of possiblelectronically applications. For example, Au is commonly used asontact material for source and drain electrodes in field effect tran-istors. Due to the thermodynamic instability in a cleaved-bulkonfiguration [12], Au reconstructs into an atomic arrangement,he so called “herringbone” reconstruction. It consists in a uniaxialompression of the topmost atomic layer along one of the three1 1 0〉 directions [13].

Various studies were done in order to understand the way thatu interacts with the substrate and to find the optimum parameters

o obtain atomically flat films. The majority of these studies focusesn the deposition of Au on mica, due to the close values of therystal parameters [14–20]. Other groups tried to deposit Au onure Si [21–26], either by using an intermediate layer of Cu [27], orn SiO2 [28].

An important aspect in thin film deposition is the thermal fac-or, such as substrate temperature and thermal annealing aftereposition. It assures a high quality thin film growth, such asrystalline films growth or epitaxy, providing additional energyor surface atoms and clusters to react and diffuse, and for sur-ace to relax and reconstruct [18]. In case of the Au films, therocess of thermal annealing is a necessary step, as it dramat-

cally improves the flatness, producing atomically flat terraces29,30].

This paper deals with the way that the thin film growth isnfluenced by the different temperatures of the substrate. We dis-ussed the case of four substrate temperatures in the range of80–630 ◦C regarding the orientation of the films, the roughnessnd the growth type. The X-ray diffractograms reveal the samerientation of the films as the substrate used, while based on theTM images we were able to calculate the roughness of the sur-aces and to compare them, taking into account the temperaturef the substrate. Our final objective is to deposit thin films withtomically flat gold terraces used as substrates for self assembledonolayers.

. Experimental

In this work we studied the morphological and structural prop-rties of 100 nm thick gold films obtained by molecular beampitaxy deposition system (Lab-10 MBE, Omicron GmbH). For theeposition of gold films, Si(1 1 1) substrates (p-type, resistivity.01 � cm) with 7 × 7 reconstruction were used. The reconstructedi(1 1 1) were obtained using a well-established annealing andashing procedure [31] and a clear 7 × 7 pattern was confirmedy the RHEED system (STAIB Instruments GmbH).

The Au thin films were deposited on Si(1 1 1) 7 × 7 recon-tructed wafers under an ultra high vacuum (∼10−10 mbar) byolecular beam epitaxy technique. The film thickness was moni-

ored using a beam flux monitor attached to the MBE depositionhamber. The deposited gold was of 99.9995% purity (Premion,lfa, Germany). We set the deposition rates at 1.6 nm/min ande varied the substrate temperature in the range 480–630 ◦C.

he substrate temperature was measured using a thermocouplettached to the MBE manipulator. After deposition, the films werennealed for 60 min at deposition temperature, then slowly cooledown to room temperature at a rate of 13 ◦C min−1. After cool-

ng the Au films, ex situ STM characterizations were performedsing a variable temperature SPM (VT-SPM by Omicron GmbH)perated under ultra high vacuum conditions. STM images were

isualized using SPIP software (Scanning Probe Image ProcessorSPIP) version 6.0.10 Image Metrology ApS, Lyngby, Denmark). Therogram was also used to evaluate roughness of deposited thinlms. Structural properties of the thin films were studied using

ace Science 288 (2014) 166– 171 167

Bruker D8 Advance X-ray Diffractometer with Cu K� radiation(� = 0.15406 nm).

3. Results and discussions

3.1. The 7 × 7 reconstruction of Si(1 1 1)

The quality of the Si substrates is illustrated in the STM imagedisplayed in Fig. 1. This image has been taken at negative samplebias (−2 V) applied to the sample, and therefore it reflects the spa-tial distribution of occupied surface electronic states (filled-stateimage). The amplificatory (7 × 7) unit cell was indicated in Fig. 1aand his size is found to be 2.7 × 2.7 nm as describe in literature [8].The line profile in Fig. 1c showed the positions and height differ-ences of the six distinct types of atoms (labeled 1–6) along the solidline represented in Fig. 1(a) and (b). Atoms 1, 2 and 3 indicate thecorner adatom, the rest atom and the center adatom in the FHUC,while 4, 5, and 6 indicate the center adatom, the rest atom and thecorner adatom in the UHUC, respectively.

Fig. 2 shows a clear Si(1 1 1) 7 × 7 surface obtained by RHEEDmeasurements. RHEED was used in deposition procedure to mon-itor the growth with an electron energy of 25 kV.

3.2. Deposition of Au films

Our first need is to develop gold thin films suitable for STM andAFM studies down to molecular resolution. It is therefore neces-sary to make films with low roughness, an important parameterto describe atomic flat Au terraces. This is achieved by deposit-ing a film thickness of 100 nm, and giving particular attentionto the cooling rate in order to avoid the formation of fracturesin the film. We investigated the influence of substrate tempera-ture on the morphology of gold film and its structural properties.A heating of the substrate during deposition process is nec-essary to obtain epitaxial thin film. Therefore, we investigatethe morphology of the films prepared in the temperature range480–630 ◦C. We present 100 nm thin gold films elaborated at fourdifferent temperatures: 480 ◦C (film 1), 530 ◦C (film 2), 580 ◦C(film 3) and 630 ◦C (film 4), with a constant deposition rate of1.6 nm/min.

3.3. XRD measurements

The orientation of the thin films was studied using X-ray diffrac-tion (XRD) in Bragg-Brentano geometry (�–2�). The scanning stepwas 0.02◦ with 0.8 s/step and �–2� range was between 10◦ and90◦. Fig. 3 represents the normalized XRD patterns of the Au thinfilms deposited on Si(1 1 1) 7 × 7 at four different substrate temper-atures.

The peak at 28.44◦ corresponding to Si substrate with Millerindices (1 1 1) was taken out from diffractograms for a bettervisualization of the peaks relating to Au thin films. It can beobserved in the XRD diffractograms that the films deposited atlower temperatures than 580 ◦C contain peaks corresponding toMiller indices (1 1 1), (2 0 0), (2 2 0) and (3 1 1) which indicate thatthese films are not only deposited by (1 1 1) direction of the Sisubstrate.

The film 3 with a substrate temperature of 580 ◦C showsonly one pick corresponding to (1 1 1) direction. All otherpeaks of Au are not identified in the XRD pattern of thethin film. This clearly suggests that the film crystallites arepreferentially oriented with (1 1 1) planes parallel to the sub-

strate [32]. With increasing temperature at 630 ◦C the peakcorresponding to (2 0 0) planes was observed. This indicatesthat the film crystallites are losing their preferential orienta-tion after (1 1 1) direction. This may be due to higher energy

168 D. Marconi, A. Ungurean / Applied Surface Science 288 (2014) 166– 171

Fig. 1. (a) The STM image of Si(1 1 1) 7 × 7 reconstruction recorded by sample bias voltagadatoms and 6 rest atoms; (c) the line profile extract along the line from b.

Fig. 2. RHEED Si(1 1 1) 7 × 7 pattern obtained after well-established annealing andflashing procedure.

Fig. 3. X-ray diffraction pattern of Au/Si(1 1 1) thin films.

e of −2 V and tunneling current of 0.3 nA; (b) the 7 × 7 unit cell with schematic 12

received by the atoms during the deposition and annealingprocesses [33]. A high substrate temperature induces defectsin the films, which influence the nucleation and growth ofthe thin films, and finally the degradation of the crystallinity[34–39].

3.4. STM characterization of the Au thin films

Table 1 resumes the considered parameters for the obtainedfilms. A very important parameter calculated by us, which describesthe quality, and more specific, the roughness of the grown films isthe root mean square (RMS) value. It should be in the range of lessthan 1 nm to assure that only atomic steps are present at the surface[15].

To characterize the Au/Si(1 1 1) films, we took into consid-eration STM images of different dimensions: above 1 �m wideSTM images for a reliable obtained RMS, and 300 nm wide STMimages for studying the results of the deposition process. The 3DSTM images used for the calculation of RMS are shown in Fig. 4,while Fig. 5 presents the morphology of the thin films at atomicscale.

The growth mode of a film falls into one of the three basic cate-gories [40]: layer (Frank and van der Merwe [41]) mode, layer plusisland (Stranski–Krastanov [42]) mode and island (Volmer–Weber[43]) mode. Our thin films show a 2D orientation, as Fig. 4 presents.Film 1 is characterized by discontinue terraces and irregularheights. The maximum height is ∼150 nm. It can be seen that thegrains seem to coalesce in forming a continuous surface, but is nota fully accomplished process, due to the insufficient energy givenby the substrate during the deposition and annealing. In case offilm 2, the maximum height is ∼4 nm, with wide terraces, sep-arated mainly by monoatomic steps. An interesting observationis related to the island present in Fig. 4(b) with the maximumheight. Our thoughts go to the existing of the nucleation site. Infact, generally, metal films on non-metal surfaces grow in a firststage in the Volmer–Weber mode as 3D islands with droplet-like shapes. According to Ruffino and Grimaldi [44], who grewAu thin films with thickness less than 100 nm, the first stage offilm growth consists in the nucleation of hemispherical Au clus-ters on the Si(1 1 1). After this stage the growth is characterized

by a coalescence of the Au clusters. By the coalescence processlarger clusters are formed. Finally, after a fully covered surfaceis reached, adsorptive growth proceeds only in the vertical direc-tion.

D. Marconi, A. Ungurean / Applied Surface Science 288 (2014) 166– 171 169

Table 1Deposition parameters for the obtained Au films.

Deposited film Deposition temperature (◦C) Deposition rate (nm/min) RMS (nm)

1 480 1.6 16.982 530 1.943 580 0.32

gpfifsiw∼hwta

Fc

4 630

For higher thicknesses, the shapes of the islands become elon-ated and only for further higher thicknesses the film takes aercolation morphology and finally becomes a continuous roughlm [45]. The temperature of 580 ◦C seems appropriate for the

ormation of atomically smooth terraces with atomic steps mea-uring 3 A in height in good agreement with [46]. The film growths layer by layer and is demonstrated in Fig. 4(c). Finally, film 4

as grown and annealed at 630 ◦C, having a maximum height of10 nm. The surface is made of flat terraces separated by deep

oles in the range of tens of atomic layers. This is incompatibleith molecular resolution STM experiments [47,48]. Comparing

he all four films, one can see the resemblance between film 2nd film 4 regarding the shape and the diameter of the grains.

ig. 4. 1.2 �m × 1.2 �m 3D STM images of the deposited thin films at different temperaturrent of 0.3 nA.

2.09

This phenomenon was also observed by Lussem et al. [17] duringthe single step process deposition of Au on mica. The morphol-ogy of the grown thin films can be clearly observed in Fig. 5.By far, film 3 has flat atomic layers, with maximum height of∼0.8 nm.

Film 1 is by far the most affected by the low depositiontemperature, its surface showing rectangular shapes of differ-ent heights. The deep holes and the incomplete terraces aremostly observed in case of film 4, due to the high deposi-

tion temperature. The maximum height is comparable with theone for film 3 (∼0.7 nm). Finally, film 2 shows multiple flatterraces, with a maximum height of ∼3.8 nm and incomplete ter-races.

ures. The STM images were recorded by sample bias voltage of 1.6 V and tunneling

170 D. Marconi, A. Ungurean / Applied Surface Science 288 (2014) 166– 171

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ig. 5. 300 nm × 300 nm STM images of deposited thin films at different temperatuf 0.3 nA.

. Conclusions

We have studied the influence of substrate temperature on thetructural and morphological properties of the Au films depositedy MBE using XRD and STM characterization.

XRD diffractograms show that the films deposited below andbove 580 ◦C are not only oriented by (1 1 1) direction of the Siubstrate.

The film deposited at 580 ◦C shows only one pick correspondingo (1 1 1) direction. All other peaks of Au are not identified in theRD pattern of the thin film which suggests that the film crystal-

ites are preferentially oriented after (1 1 1) planes parallel to theubstrate.

From STM measurements it was been found that the filmeposited at 580 ◦C has a good compromise between flat Au terraceshich is larger than 100 nm and roughness amplitude, a necessary

ondition to perform STM experiments.

cknowledgements

This work was possible with the financial support fromEFISCDI, projects PN-II-ID-PCCE-2011-2-0027 “Ion sensing and

e STM images were recorded by sample bias voltage of 1.6 V and tunneling current

separation through modified cyclic peptides, cyclodextrins andprotein pores” and PN-II-PT-PCCA-2011-3.1-0595 “Rational designand generation of synthetic, short antimicrobial peptides. Linkingstructure to function”, which are highly acknowledged. The authorswould like to thank PhD Student Maria Miclaus for XRD measure-ments.

References

[1] K. Seshan, Handbook of Thin-Film Deposition Processes and Techniques.Principles, Methods, Equipment and Applications, 2nd ed., Noyes Publica-tions/William Andrew Publishing, Norwich, New York, 2002.

[2] V.M. Ievlev, Thin-film nanostructures: substructural aspects, Inorg. Mater. 40(2004) S71–S90.

[3] J.R. Arthur, Molecular beam epitaxy, Surf. Sci. 500 (2002) 189–217.[4] D.D. Vvedensky, Epitaxial phenomena across length and time scales, Surf. Inter-

face Anal. 31 (2001) 627–636.[5] D.E. Hooks, T. Fritz, M.D. Ward, Epitaxy and molecular organization on solid

substrates, Adv. Mater. 13 (2001) 227–241.[6] F.M. Nakhei, A. Bahari, Topography measurement of nano silicon oxide film,

Int. J. Phys. Sci. 4 (2009) 290–293.

[7] K. Takayanagi, Structural analysis of Si(1 1 1)-7 × 7 by UHV-transmission elec-

tron diffraction and microscopy, J. Vac. Sci. Technol. A 3 (1985) 1502–1506.[8] Y.-L. Wang, H.-M. Guo, Z.-H. Qin, H.-F. Ma, H.-J. Gao, Toward a detailed

understanding of Si(1 1 1)-7 × 7 surface and adsorbed Ge nanostructures: fab-rications, structures, and calculations, J. Nanomater. 2008 (2008) 1–18.

d Surf

[

[

[

[

[

[

[

[

[

[

[

[

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[

[

[

[

[

[

[

[[

[

[

[

[

[

[

[[

[

[

[

[

[

D. Marconi, A. Ungurean / Applie

[9] M.A. Lantz, H.J. Hug, P.J. van Schendel, R. Hoffmann, S. Martin, A. Baratoff,A. Abdurixit, H. Guntherodt, C. Gerber, Low temperature scanning forcemicroscopy of the Si(1 1 1)-(7 × 7) surface, Phys. Rev. Lett. 84 (2000)2642–2645.

10] F.J. Giessibl, Atomic resolution of the silicon(1 1 1)-(7 × 7) surface by atomicforce microscopy, Science 267 (1995) 68–71.

11] F.J. Giessibl, Subatomic features on the silicon(1 1 1)-(7 × 7) surface observedby atomic force microscopy, Science 289 (2000) 422–425.

12] H.J. Gao, L. Gao, Scanning tunneling microscopy of functional nanostructureson solid surfaces: manipulation, self-assembly, and applications, Prog. Surf. Sci.85 (2010) 28–91.

13] F. Reinert, G. Nicolay, Influence of the herringbone reconstruction on the surfaceelectronic structure of Au(1 1 1), Appl. Phys. A: Mater. Sci. Process. 78 (2004)817–821.

14] J.A. DeRose, T. Thundat, L.A. Nagahara, S.M. Lindsay, Gold grown epitaxially onmica: conditions for large area flat faces, Surf. Sci. 256 (1991) 102–108.

15] U. Hopfner, H. Hehl, L. Brehmer, Preparation of ordered thin gold films, Appl.Surf. Sci. 152 (1999) 259–265.

16] P. Kowalczyk, W. Kozlowski, Z. Klusek, W. Olejniczak, P.K. Datta, STM studiesof the reconstructed Au(1 1 1) thin-film at elevated temperatures, Appl. Surf.Sci. 253 (2007) 4715–4720.

17] B. Lüssem, S. Karthäuser, H. Haselier, R. Waser, The origin of faceting of ultraflatgold films epitaxially grown on mica, Appl. Surf. Sci. 249 (2005) 197–202.

18] L. Nan, D. Allan, L.G. Yu, In situ STM study of thermal annealing of Au thin films:an investigation on decay of nanometer Au clusters and 2D islands, Acta Phys.Sin. -Overseas Ed. 6 (1997) 531–549.

19] C. Nogues, M. Wanunu, A rapid approach to reproducible, atomically flat goldfilms on mica, Surf. Sci. 573 (2004) L383–L389.

20] A. Putnam, B.L. Blackford, M.H. Jericho, M.O. Watanabe, Surface topographystudy of gold deposited on mica using scanning tunneling microscopy: effectof mica temperature, Surf. Sci. 217 (1989) 276–288.

21] T. Hasegawa, Initial stage of Au adsorption onto a Si(1 1 1) surface studied byscanning tunneling microscopy, J. Vac. Sci. Technol. B 9 (1991) 758–760.

22] J. Yuhara, Phase transition of the Si(1 1 1)–Au surface from√

3 × √3 to 5 × 1

structure studied by means of the low-energy electron diffraction, Auger elec-tron spectroscopy, and Rutherford backscattering spectroscopy techniques, J.Vac. Sci. Technol. A 10 (1992) 334–338.

23] K. Pedersen, T.B. Kristensen, T.G. Pedersen, T. Jensen, P. Morgen, Z. Li, S.V. Hoff-mann, Characterisation of Au films on Si(1 1 1)

√3 × √

3–Au by photoemissionand optical second harmonic generation, Surf. Sci. 523 (2003) 21–29.

24] S. Klages, M. Schock, C. Surgers, H.v. Lohneysen, Electronic transport in ultrathingold films on Si(1 1 1), J. Low Temp. Phys. 137 (2004) 509–522.

25] R. Daudin, T. Nogaret, T.U. Schülli, N. Jakse, A. Pasturel, G. Renaud, Epitaxialorientation changes in a dewetting gold film on Si(1 1 1), Phys. Rev. B 86 (2012)094103 (1)–(8).

26] D.A. Tsukanov, M.V. Ryzhkova, E.A. Borisenko, L.V. Bondarenko, A.V. Matetskiy,D.V. Gruznev, A.V. Zotov, A.A. Saranin, Surface conduction at phase transitions

in (Au, Ag)/Si(1 1 1) submonolayer films, Appl. Surf. Sci. 258 (2012) 9636–9641.

27] A. Silva, K. Pedersen, L. Diekhoner, P. Morgen, Z. Li, Ordered Au(1 1 1) layers onSi(1 1 1), J. Vac. Sci. Technol. A 25 (2007) 908–911.

28] V.L. De Los Santos, D. Lee, J. Seo, F.L. Leon, D.A. Bustamante, S. Suzuki, Y. Majima,T. Mitrelias, A. Ionescu, C.H.W. Barnes, Crystallization and surface morphology

[

[

ace Science 288 (2014) 166– 171 171

of Au/SiO2 thin films following furnace and flame annealing, Surf. Sci. 603(2009) 2978–2985.

29] S. Buchholz, H. Fuchs, J.P. Rabe, Surface structure of thin metallic films on micaas seen by scanning tunneling microscopy, scanning electron microscopy, andlow-energy electron diffraction, J. Vac. Sci. Technol. B 9 (1991) 857–861.

30] M.H. Dishner, M.M. Ivey, S. Gorer, J.C. Hemminger, F.J. Feher, Preparation of goldthin films by epitaxial growth on mica and the effect of flame annealing, J. Vac.Sci. Technol. A 16 (1998) 3295–3300.

31] D.R.T. Zahn, S. Seifert, G. Gavrila, W. Braun, Investigation of bio-organic/inorganic semiconductor interfaces, J. Optoelectron. Adv. Mater. 9(2007) 522–526.

32] W.M. Bullis, Properties of gold in silicon, Solid-State Electron. 9 (1966) 143–168.33] M. Khaleeq-ur-Rahman, K.A. Bhatti, M.S. Rafique, S. Anjum, A. Latif, M. Anjum, A.

Ahsan, H. Ozair, Morphological and structural analysis of nano-structured goldthin film on silicon by pulsed laser deposition technique, Vacuum 85 (2010)353–357.

34] B.A. Movchan, A.V. Demchishin, Obtaining depositions during vacuum conden-sation of metals and alloys, Fiz. Met. Metalloved. 28 (1969) 653–660.

35] J.A. Thornton, High rate thick film growth, Annu. Rev. Mater. Sci. 7 (1977)239–260.

36] C.R.M. Grovenor, H.T.G. Hentzell, D.A. Smith, The development of grain struc-ture during growth of metallic films, Acta Metallogr. 32 (1984) 773–781.

37] R. Messier, A.P. Giri, R.A. Roy, Revised structure zone model for thin film physicalstructure, J. Vac. Sci. Technol. A 2 (1984) 500–503.

38] P.B. Barna, M. Adamik, Fundamental structure forming phenomena of poly-crystalline films and the structure zone models, Thin Solid Films 317 (1998)27–33.

39] M. Higo, K. Fujita, Y. Tanaka, M. Mitsushio, T. Yoshidome, Surface morphologyof metal films deposited on mica at various temperatures observed by atomicforce microscopy, Appl. Surf. Sci. 252 (2006) 5083–5099.

40] R.W. Vook, B. Oral, The epitaxy of gold, Gold Bull. 20 (1987) 13–20.41] F.C. Frank, J.H. van der Merwe, One-dimensional dislocations. I. Static theory,

Proc. R. Soc. Lond., Ser. A 198 (1949) 205–216.42] I.N. Stranski, L. Krastanov, Zur Theorie der orientierten Ausscheidung von

Ionenkristallen aufeinander, Sitzungsber, Akad. Wiss. Wien. Math.-Naturwiss.Kl. IIb 146 (1938) 797–810.

43] M. Volmer, A. Weber, Keimbildung in ubersattigten Gebilden, Z. Phys. Chem.119 (1926) 277–301.

44] F. Ruffino, M.G. Grimaldi, Atomic force microscopy study of the growth mech-anisms of nanostructured sputtered Au film on Si(1 1 1): evolution with filmthickness and annealing time, J. Appl. Phys. 107 (2010) 104321.

45] F. Ruffino, V. Torrisi, G. Marletta, M. Grimaldi, Atomic force microscopy investi-gation of the kinetic growth mechanisms of sputtered nanostructured Au filmon mica: towards a nanoscale morphology control, Nanoscale Res. Lett. 6 (2011)112.

46] E. Holland-Moritz, J. Gordon, G. Borges, R. Sonnenfeld, Motion of atomic stepsof gold(1 1 1) films on mica, Langmuir 7 (1991) 301–306.

47] H. Klein, W. Blanc, R. Pierrisnard, C. Fauquet, P. Dumas, Self-assembledmonolayers of decanethiol on Au(1 1 1)/mica, Eur. Phys. J. B 14 (2000)371–376.

48] S.H. Leuba, J. Zlatanova, Biology at the Single Molecule Level, 1st ed., Pergamon,New York, 2001.