March 19, 2007S. A. Getty NASA Headquarters ESMD Faculty-Student Research Team: Nanotechnology for...

March 19, 2007 S. A. Getty NASA Headquarters

ESMD Faculty-Student Research Team: ESMD Faculty-Student Research Team: Nanotechnology for Exploration and ScienceNanotechnology for Exploration and Science

Dr. Stephanie A. GettyNASA GSFCCode 541

Materials Engineering Branch

Applied Nanotechnology

Prof. David D. AllredBrigham Young University

Dept. of Physics and AstronomyStudents: Jonathon Brame

Johnathan Goodsell


NASA’s Exploration InitiativeNASA’s Exploration InitiativeCourtesy NASA website

To the Moon, Mars and Beyond

The Vision for Space Exploration calls for humans to return to the moon by the end of the next decade, paving the way for eventual journeys to Mars and beyond.

Courtesy NASA website

To the Moon, Mars and Beyond

The Vision for Space Exploration calls for humans to return to the moon by the end of the next decade, paving the way for eventual journeys to Mars and beyond.

Carbon Nanotube- Magnetic analysis of geological based Magnetometer : samples on Mars and the Moon

Orientation for manned expeditionsLocation of mining resources


Projects ongoing in GSFC NanoDevices GroupProjects ongoing in GSFC NanoDevices Group

– Strain-based NanoCompass• GSFC: 541, 691 • BYU summer intern team: Prof. D. Allred, Johnathan

Goodsell, Jon Brame

– Electron gun for miniaturized mass spectrometer• GSFC: 541, 553, 699 • Fisk University summer intern: Melissa Harrison

– Generalized strain sensors• GSFC: 541, 660 • BYU summer intern team: Prof. D. Allred, Johnathan

Goodsell, Jon Brame• Fisk University summer intern: Melissa Harrison


Background Information:Background Information:Carbon NanotubesCarbon Nanotubes


Nanoelectronic MaterialsNanoelectronic MaterialsSingle-walled Carbon

Nanotubes

• Metallic or Semiconducting– Difficult to control trend toward

SWCNT network devices

• Electronic properties sensitive to deformation– Strain sensing

Courtesy Smalley Group, Rice Univ.


Vapor-Liquid-Solid GrowthVapor-Liquid-Solid GrowthFeedstock gas liquid alloy solid nanostructure

SWCNTs:•Catalyst = Fe(NO3)3:IPA or thin film Fe•Feedstock = CH4 and C2H4

•TG = 950°C, tG = 5-10 minutes

MWCNTs:•Catalyst = thin film Al/Fe bilayer•Feedstock = C2H4

•TG = 750°C, tG = 5-10 minutes


Thin Film Fe CatalystThin Film Fe Catalyst

• High density

• Improved cleanliness

20 nm

TEM studies show–SWCNTs –MWCNTs–bundles

TG = 950°C

NanoCompass

Johnathan Goodsell, Prof. David Allred, Prof. R. Vanfleet (BYU)


Summary of Progress: SWCNT GrowthSummary of Progress: SWCNT Growth

• Johnathan Goodsell – Brigham Young University– Mechanical Engineering Major

• Summer project: Optimize growth of SWCNTs using thin film catalyst– New process for GSFC– Crucial for NanoCompass development

• Excellent results in only 8 weeks – Contributed to IEEE Nano 2006 Presentation,

Cincinnati, OH, July 2006


SWCNT NanoCompass for High SWCNT NanoCompass for High Spatial Resolution MagnetometrySpatial Resolution Magnetometry


Applications:• Magnetospheric Science• Spacecraft Orientation• Planetary Geomagnetism

but• cm-scale resolution• Limited materials supply

Fluxgate Magnetometer:• High sensitivity (nTesla)• Low noise

M. H. Acuna, Rev. Sci. Inst. 73, 3717 (2002)

Technological MotivationTechnological MotivationMars


NanoCompass DesignNanoCompass Design

● Au Electrodes

Single-Walled Carbon Nanotubes ● Ferromagnetic Needle Mech coupled to SWCNTs Deflected in Magnetic Field

NanoCompass


Projected SpecificationsProjected Specifications

NanoCompass (estimated)

UCLA fluxgate (ST5)

Max Op Temp ~450°C 100°C

Sensor Dimensions

10-5 cm x 10-5 cm on Si (scalable)

4 cm x 4 cm x 6 cm

Sensor [Array] Mass

1 g 75 g

Sensor Op Power 10-3 - 10-2 mW 50 mW


NanoCompass Fabrication (to step 4)NanoCompass Fabrication (to step 4)

Materials can be robust to fabrication process

Next steps:• Reduce electrode

spacing• Reduce needle width• Increase trench depth

NanoCompass


Future Work: Variability in ProcessingFuture Work: Variability in Processing

• SWCNT device electrically intact

• During magnetic field testing, continuity lost

• Next prototype in progress

Au

Au

SWCNTs

Remnantneedle


Generalized Strain Sensing Generalized Strain Sensing Using SWCNTsUsing SWCNTs


Flexible substratesFlexible substrates• Parylene, PDMS are candidates

– Modular electromechanical strain sensors– Modular field emitters– Application-adaptive devices

• Parylene: vapor-phase coated polymer, highly chemically resistant, excellent electronic insulator

• PDMS: polydimethylsiloxane, two-part curable elastomer, chemically resistant, good electronic insulator – to be demonstrated in SWCNTs


Device Transfer to ParyleneDevice Transfer to Parylene

O2 plasma 3. Transfer to PDMS by substrate removal

1. Fabricate SWCNT device on rigid substrate to allow electrical characterization

Wet etch

2. Deposit parylene


Parylene-bound SWCNT Strain DeviceParylene-bound SWCNT Strain DeviceFlexible Substrates

Jonathon Brame, Prof. David Allred (BYU)


Preliminary ResultsPreliminary Results

• Large increase in device resistance with application of strain, as expected

• Need to separate contact effects from piezoresistive effects

• Need to evaluate reproducibility

The slope of the lines between 4µm stretch sets indicates that the resistance increases reversibly with increased strain.

Flexible Substrates


Summary of Progress: Parylene-bound SWCNT Summary of Progress: Parylene-bound SWCNT DevicesDevices

• Jonathon Brame – Brigham Young University– Physics Major

• Summer project:– Demonstrate transfer of SWCNTs to parylene substrates– Test electromechanical response

• Preliminary fabrication and test completed in only 12 weeks – Publication and presentation at MRS Fall Meeting, Boston,

November 2006– “Strain-based Electrical Properties of Systems of Carbon

Nanotubes Embedded in Parylene,” Jon Brame, Stephanie Getty, Johnathan Goodsell, and David Dean Allred, Proceedings, Materials Research Society Fall 2006 Meeting.


Status of Collaboration: GSFC-BYU TeamStatus of Collaboration: GSFC-BYU Team

• BYU Team has major role in Mars Desert Research Station (UT) – In situ demonstration of NanoCompass operation– Student-operated for outreach effort– Relevant to manned missions to the Moon and Mars

• Joint proposal submitted to support NanoCompass:– ROSES Planetary Instrument Definition and Development– Decision Pending

• Building growth/characterization facility at BYU– Correlated results, independent of location, important to the

CNT field– Measurements of CNT response in extreme UV planned– Possible applications in nanomaterial sensing for workplace

safety monitoring


AcknowledgementsAcknowledgements• Dr. Peter Wasilewski GSFC/Astrochemistry Laboratory

• Dr. Louis Barbier GSFC/Exploration of the Universe Division

• Dr. Paul Mahaffy GSFC/Atmospheric Experiments Laboratory

• Patrick Roman GSFC/Detector Systems Branch

• Barney Lynch GSFC/Detector Systems Branch

• Dr. Federico Herrero GSFC/Detector Systems Branch

• Rusty Jones GSFC/Detector Systems Branch

• Dr. Todd King GSFC/Materials Engineering Branch

• Rachael Bis GSFC/Materials Engineering Branch

• Michael Beamesderfer GSFC/Materials Engineering Branch

• Lance Delzeit ARC/Nanotechnology Branch

• Prof. Gunther Kletetschka GSFC/Catholic University of America

• Vilem Mikula GSFC/Catholic University of America

• Tomoko Adachi GSFC/Catholic University of AmericaESMD Summer Internship Program

• Prof. David Allred Brigham Young University/Dept. of Physics & Astronomy

• Prof. Richard Vanfleet Brigham Young University/Dept. of Physics & Astronomy

• Johnathan Goodsell Brigham Young University/Mechanical Engineering Dept.

• Jonathon Brame Brigham Young University/Dept. of Physics & Astronomy MUCERPI Summer Internship Program

• Melissa Harrison Fisk UniversityThis work was supported by the Goddard Space Flight Center Director’s Discretionary Fund, the GSFC IRAD Program,

the Minority University College Education and Research Partnership Initiative, and the Exploration Systems Mission Directorate Faculty-Student Summer Internship Program


Extra SlidesExtra Slides


Nanoelectronic MaterialsNanoelectronic MaterialsSingle-walled Carbon Nanotubes

• Characterized by chirality, diameter– Diameter ~ 1 nm

• Metallic or Semiconducting– Difficult to control trend toward

SWCNT network devices

• Electronic properties sensitive to deformation– Strain sensing Courtesy Smalley Group, Rice Univ.

Courtesy Fuhrer Group, Univ Maryland, College Park

Metallic SWCNT:

n – m = 3 x integer


Nanoelectronic Materials, Cont.Nanoelectronic Materials, Cont.Multi-walled Carbon Nanotubes

• Exclusively metallic– Similar to graphite

• Diameters 30-100 nm– Larger than SWCNTs

• High aspect ratio with many

available electrons– Field emission


E-gun for MEMS Time-of-Flight Planetary Atmospheric ScienceMass Spectrometer : and biologically significant

molecular species for astrobiology

Ion lens assembly prototype

Carbon Nanotube-based Electron Gun


Comparison: Candidate TechnologiesComparison: Candidate Technologies

MWCNTs

Spindt Emitters

Thermionic

Type

MetricCNT Field

EmitterSpindt

EmitterThermionic

Emitter

Density 1010 /cm2* 5x107 /cm2† 1 /cm2

Current @ Voltage

100μA @ 50V**1mA @

150 V*

Operating Temp

Ambient Ambient >700°C¶

Redundancy (2mm diam)

3x108 106 1

*This work **Optimized†V. M. Aguero and R. C. Adamo, 6th Spacecraft Charging Technology Conference (2000).¶Barium Oxide-coated Tungsten

Field Emission


• CNT tower dimensions – 5 μm x 5 μm x

10 μm (height)

• 50 μm pitch• 2mm x 2mm

array

Field Emission

Patterned CNT CathodePatterned CNT Cathode


Patterned MWCNTs for High Patterned MWCNTs for High Performance E-gunPerformance E-gun

GSFC patterned MWCNT emitter:

• Cathode-grid spacing = 140 µm

• Turn-on voltage <100 V

• 50 µA @ 10 mW

Compare to Cassini-Huygens thermionic e-gun:

• 80 µA @ 1000 mW

Field Emission

-8 10-6

0

8 10-6

1.6 10-5

2.4 10-5

3.2 10-5

4 10-5

4.8 10-5

-2 10-12

0

2 10-12

4 10-12

6 10-12

8 10-12

1 10-11

1.2 10-11

0 50 100 150 200

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

-Em

issi

on C

urr

ent

(A

)

-Em

ission C

urre

nt Den

sity (A/um

2)

Extraction Voltage (V; grid bias)

Electric Field (V/m)

0.6 0.7 0.8 0.9 1 1.1 1.2-30

-29

-28

-27

-26

-25

ln(J/E2)

1/E

Fit to Fowler-Nordheim Tunneling:

J = K1E2 exp(-K

2/E)


-50

0.0

50

1.0 102

1.5 102

2.0 102

2.5 102

3.0 102

3.5 102

-50

0

50

100

150

200

250

300

350

-20 0 20 40 60 80 100 120 140

Turn-on voltage versus Cathode-Grid SpacingT

urn

-on

Vo

ltag

e (

V)

Cathode-Grid Spacing (um)

ARC1

GSFC060802-2GSFC060802-2

ARC2-21

ARC2-11

GSFC060803-1 GSFCpattern-1ARC2-22

GSFC:EGp2

Sample DatabaseSample Database

Best performer:– GSFC patterned

sample– 50 uA @ gap =

140 um

Field Emission


Side-by-Side E-Gun EvaluationSide-by-Side E-Gun EvaluationField Emission

Recent and Upcoming Work:Compare candidate e-gun technologies, fully integrated with aperture/lens stack

lens stack

filament

repeller

Towards Integration into MEMS Time-of-Flight Mass Spectrometer

CNT e-gunThermionic e-gun


Future Work for Summer Interns: CNT E-GunFuture Work for Summer Interns: CNT E-Gun

• Lifetime testing of CNT emitters• Study of performance in ambient gas

environment• Maturation of fabrication techniques• Maturation of packaging techniques• Advanced electronics to develop

feedback/ballast for current stabilization

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March 19, 2007S. A. Getty NASA Headquarters ESMD Faculty-Student Research Team: Nanotechnology for...

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