Nano- and Microtechnology Development 

for Advanced Scientific Measurements 

throughout the Solar System 

Adrian Southard, Yun Zheng, Stephanie A. Getty

NASA Goddard Space Flight Center

September 13, 2010
September 13, 2010 A. Southard/NASA GSFC 2

Goddard Space Flight Center

NASA Centers (10):

+ Ames Research Center

+ Dryden Flight Research Center

+ Glenn Research Center at Lewis Field

+ Goddard Space Flight Center

+ Jet Propulsion Laboratory

+ Johnson Space Center

+ Kennedy Space Center

+ Langley Research Center

+ Marshall Space Flight Center

+ Stennis Space Center
Nano and Microfabrication Facilities

September 13, 2010 A. Southard/NASA GSFC 3

SWCNT and MWCNT growth

Scanning Electron Microscopy
September 13, 2010 A. Southard/NASA GSFC 4

Planetary Targets for In Situ Instruments

Mars

Wild 2

Eros

Icy Small Bodies: Asteroids

Titan

Tempel 1

Icy Small Bodies: Comets

Europa

Mars

Jupiter

Saturn

Europa

Enceladus

Titan

Comet Wild 2

Aerogel 

Sample 

Capture
Mass Spectrometry

• Well established technique for in situ 

chemical analysis in planetary science 

missions

• Provides mass-to-charge ratio for every 

sample constituent – non-specific

• Can be interfaced to complementary 

analytical techniques for thorough sample 

characterization, e.g.

– Pyrolysis (soil)

Thermally evolved volatiles

– Gas chromatography

(atmosphere, pyrolysis products)

Small, robust molecules

– Liquid chromatography

(soil extract, liquid)

Complex molecules

September 13, 2010 A. Southard/NASA GSFC 5

Applications:

• Magnetospheric Science

• Spacecraft Orientation

• Planetary Geomagnetism

Mars

Titan

Enceladus
September 13, 2010 A. Southard/NASA GSFC 6

Planetary Mass Spec: State of the Art

Gas Chromatograph Quadrupole 

Mass Spectrometer

– part of Huygens lander 

– Cassini mission to Saturn and 

moons

Titan

• Quadrupole mass filter uses AC 

fields to select transmission at a 

single mass

• Mass spectrum is acquired by 

scanning through operating range

• Thermionic filaments are used for 

electron impact ionization of gas
September 13, 2010 A. Southard/NASA GSFC 7

Planetary Mass Spec: State of the Art

Pyrolysis Gas Chromatograph 

Quadrupole Mass Spectrometer

– part of Sample Analysis at Mars 

Instrument Suite 

– Mars Science Laboratory rover 

mission

Mars

• QMS similar to Huygens

– m ~ 1.3 kg, P ~14.5 W

• Thermionic filaments are used 

to ionize pyrolysis products or 

atmospheric gases
September 13, 2010 A. Southard/NASA GSFC 8

In Development: Miniaturized Time-of-Flight Mass 

Spectrometer

• Time-of-Flight Mass 

Spectrometer

– Field emission Electron Gun

for electron impact ionization

– Ions are accelerated to a 

uniform kinetic energy in the 

Ion Lens Assembly

– Heavier masses travel more 

slowly than light ones in the 

Reflectron analyzer

– Arrival of isomass ion 

packets is registered as a 

function of time at the 

Microchannel Plate 

Detector
September 13, 2010 A. Southard/NASA GSFC 9

Ionization for Time-of-Flight Mass Spectrometer

600 Da 601 Da
September 13, 2010 A. Southard/NASA GSFC 10

Previous Work: Field Emission in CNTs

• SWCNT, MWCNT, and CNF

– Various growth techniques

Selected References 

• A. G. Rinzler et al., Science 269, 1550 (1995). 

• W. A. de Heer, A. Chatelain, D. Ugarte, Science 270, 1179 (1995). 

• P. G. Collins and A. Zettl, Appl. Phys. Lett. 69, 1969 (1996). 

• Q. H. Wang et al., Appl. Phys. Lett. 70, 3308 (1997).

• J.-M. Bonard, et al., Appl. Phys. Lett. 73, 918 (1998).

• W. Zhu et al., Appl. Phys. Lett. 75, 873 (1999).

• S. Fan et al., Science 283, 512 (1999). 

• X. Xu and G. R. Brandes, Appl. Phys. Lett. 74, 2549 (1999).

• N. de Jonge and J.-M. Bonard, Phil. Trans. R. Soc. London A 362, 2239 (2004).

• E. Minoux et al., Nano Lett. 5, 2135 (2005).

Patterned MWCNTs:

MWCNTs: S. Fan et al. (1999)

P. G. Collins and A. Zettl (1996)

SWCNTs:

J.-M. Bonard, et al. (1998)

CNFs:

E. Minoux et al. (2005)

Our approach:

Tower x-section << spacing
September 13, 2010 A. Southard/NASA GSFC 11

Previous Work: Field Emission in CNTs

• Fowler-Nordheim Tunneling

–Field enhancement factor

–Reported values 400-1200 

(for MWCNTs)

E

K

J K E

2 2

1

exp

3/ 2

2

B

K

W. A. de Heer, A. Chatelain, D. Ugarte (1995)
September 13, 2010 A. Southard/NASA GSFC 12

Carbon Nanotube Electron Gun

Grid

CNTs

Cathode

Insulator

Electron Beam

Anode

+

+

+

+

+

+

To TOF-MS

Analyzer

Carbon Nanotube field emitters

– Low power (100x < thermionic)

– Scalable for high sensitivity, redundancy

– Efficient ionization of the parent species

– Challenges: Lifetime and stability

Sample 

Gas
September 13, 2010 A. Southard/NASA GSFC 13

Recent Work: Assembly and Integration

Cathode-grid integration
September 13, 2010 A. Southard/NASA GSFC 14

CNT E-gun for Mini Mass Spec

• Low operating voltages 

achieved for efficient gas 

ionization

• Fowler-Nordheim 

behavior confirmed

– Field enhancement 

factor ~ 900

• Microamps of transmitted 

current in triode mode

• Persists for several 

hundred hours in high 

vacuum
September 13, 2010 A. Southard/NASA GSFC 15

CNT E-gun for Mini Mass Spec

MEMS Integration of CNT e-gun for clean packaging

• Long lifetime

• Reduced current noise

• Reliable fabrication

lenses

Ion Lens Assembly

Flight region

Flight region

Ion Lens Assembly

E-gun
TOF-MS Integrated Testing

September 13, 2010 A. Southard/NASA GSFC 16
September 13, 2010 A. Southard/NASA GSFC 17

Lens Optimization

Underfocused

Simulation of

Configuration F

Focal plane coincident with 

Ionization region

Experiment
Integrated TOF-MS Performance

• Mass resolution > 270 

September 13, 2010 MCP Counts

Time (μs)

A. Southard/NASA GSFC 18
Future Steps

• Opportunities for TOF performance improvement:

– Increased sensitivity

Electron current –

• Better transmission through revised geometry

• Optimized emitter geometry

• Pulsed e-gun

Ion transmission –

• Improve field uniformity to increase ion yield

– Increased mass resolution

• Reduce ionization volume

• Minimize rise time on pulse electronics

– Improved emitter lifetime

September 13, 2010 A. Southard/NASA GSFC 19
September 13, 2010 A. Southard/NASA GSFC 20

Liquid Chromatography-Mass Spectrometry
September 13, 2010 A. Southard/NASA GSFC 21

Miniaturized liquid chromatograph

Successful lab techniques  planetary surface

• Nanoelectronic charge displacement detector at output 

• Chemicals elute at different rates based on interactions with LC column

• Data = retention time spectrum

Miniaturize liquid 

chromatograph for in 

situ organics analysis Charge 

displacement 

detector

Electrospray 

Ionization
Chemical Separation by Liquid 

Chromatography

September 13, 2010 A. Southard/NASA GSFC 22

+

+

+

+

+

+

Laser-induced Fluorescence

LIF Signal

Retention Time

+

+

+

+

+

+

+

+

+

+
Design of Micro-LC column

September 13, 2010 A. Southard/NASA GSFC 23

40 mm

60 mm

80 mm

100 mm

• Packing of microbeads

to form stationary 

phase

• Longer channels → 

can better distinguish 

retention times, but 

higher pressure 

requirements

• Designed micro 

channels with varying 

lengths, 40 mm-100 

mm using wafer scale 

processing.

Filling of a Micro-LC column

Microbeads
September 13, 2010 A. Southard/NASA GSFC 24

ChemFET as charge displacement detector

Advantages:

• Fully electronic

– Microwatts 

• Non-specific 

– ChemFET can 

detect any organic 

species...

– ...but requires 

careful calibration

•Nanoscale

–Redundancy can reduce risk

•Integratable with Si-based technologies

–Can enable new on-chip functionality (measure pH, flow 

rate, buffer concentration)
September 13, 2010 A. Southard/NASA GSFC 25

Electronic Means of Chem/Bio Detection

Requirements

Sensitive/Selective 

Low Power and Compact

Electronically Addressable

Autonomously Operable

Robust and Reliable

Silicon Nanowires

• Nanoscale diameter

•Single-NW limit attainable

•Scalable for manufacturability 

and redundancy

Parameter SiNW

Metallic or Semiconducting Semiconducting

Sensor-DNA probe Direct surface 

attachment

Channel orientation Aligned on array

Growth temperature 450°C
26

SiNW ChemFET

• SiNW fabrication – wafer-scale 

manufacturability demonstrated

– Wafer-scale pillar growth for 

control of nanowire placement

– Near 100% NW device yield

– Excellent device uniformity

10 um

Transistor = current modulation 

with gate voltage

Electrode Electrode

SiNW

device

September 13, 2010 A. Southard/NASA GSFC

Devices

Pyrex chip 

w/ microchannel

Ferrule 

access via
Electrospray ionization

September 13, 2010 A. Southard/NASA GSFC 27

http://www.magnet.fsu.edu/education/tutorials/tools/ionization_esi.html
28

Addition of a lens to the ESI nozzle

New design of ESI nozzle

Si Anode

Insulator

Si Cathode 

Design features: 

• Can be tested with a commercial mass 

spectrometer and is compatible with microLC and 

TOF MS.

• Utilizes micro-nozzle to enhance atomization of 

jet.

• Electrodes facilitate formation of an ion beam

• Achieves high electric field for efficient charging 

of analyte without using high voltages
Future Work

• Explore SiNW surface functionalization

– Specificity

– Multiplexing

• Liquid sample extraction

– Extraction from solid samples

– Concentration of analyte

• Miniaturized liquid sample handling components e.g. 

valves, pumps

• Higher aspect ratio nozzles

September 13, 2010 A. Southard/NASA GSFC 29
September 13, 2010 A. Southard/NASA GSFC 30

Conclusions

• But this is just one facet of technology development at 

NASA...

– Earth-observing instruments

– Astronomical instruments

– Spacecraft structures

– Propulsion

– Human spaceflight

Highly interdisciplinary work

End-to-end systems development
September 13, 2010 A. Southard/NASA GSFC 31

Acknowledgements

GSFC Materials Engineering Branch

• Todd King

• Dan Stewart

• Dewey Dove

• Bruno Munoz

• Rachael Bis

• Jonathon Brame (Summer Intern)

• Nathan Woods (Summer Intern)

GSFC Detector Systems Branch

• Yun Zheng

• Manuel Balvin

• Carolina Gallardo

• David Franz

• Harold Isenberg

• Carl Kotecki

• Mary Li

• Nick Costen

• Larry Hess

• Patrick Roman

UMCP

• Mel Gomez 

• Konrad Aschenbach

NCI ATC

• Javed Khan

• Belhu Metaferia

• Jun Wei

• Young Song

NIH/NCI

• Piotr Grodzinski

• Eric Hale

• Jerry Lee

• Nicholas Panaro

This work was supported by the NCI NanoBioSensor Initiative and the GSFC 

Internal Research and Development Program

GSFC Astrochemistry Lab

•Jason Dworkin

•Mildred Martin

GSFC Atmospheric Experiments Lab

•Paul Mahaffy

•Daniel Glavin

•Jennifer Eigenbrode

•William Brinckerhoff

GSFC Planetary Magnetospheres Lab

•Bill Farrell

•Telana Jackson

•Haydee Aguilar

CUA/Astrochemistry Lab

•Gunther Kletetschka

•Tomoko Adachi

•Vilem Mikula
Please contact Stephanie Getty for more 

information or opportunities to collaborate.

Stephanie Getty

Atmospheric Experiments Laboratory

Materials Engineering Branch

Stephanie.A.Getty@nasa.gov

301-286-9760

Thank you for your attention.