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FUNCTIONAL HYBRID NANOSTRUCTURES CAPABILITIES
Synthesis
of SWNT’s, NT Arrays, NW’s, NP’s or thin films
by CVD, Laser Vaporization, and PLD with in
situ diagnostics
- ns-Laser
Vaporization Synthesis of SWNTs, NWs, NPs
SWNTs
and nanowires are produced by pulsed Nd:YAG laser-irradiation
(30 Hz, Q-switched or free-running) of composite pellets in a 2" tube
furnace with variable pressure control. Excimer laser ablation
of materials into variable pressure background gases is used for
nanoparticle generation
in proximity of ns-laser diagnostics.
- High-power ms-laser vaporization
bulk production of nanomaterials
SWNTs (primarily), SWNH
(single-wall carbon nanohorns), nanoparticles
and nanowires are produced by robotically-scanned 600W Nd:YAG
laser-irradiation (1064 nm) of targets at controlled pressure
in various atmospheres
(including CVD gases) at <1200°C inside a 3" tube
furnace. Rapid sampling capability.
- ns-Laser
Vaporization Synthesis of nanoparticles
Excimer laser ablation of materials into variable pressure background gases is used for nanoparticle generation in proximity of ns-laser diagnostics (located outside of the CNMS).
- Gated ICCD imaging
and spectroscopy of laser vaporization processes
Intensified
CCD-array photography (5-ns resolution) and intensified,
gated diode-array spectroscopy of laser vaporization plumes
and nanomaterial synthesis processes. Utilizes 2" windowed
tube furnace for nanotubes and nanowires (variable pressure,
controlled
flow) or PLD chamber.
Secondary laser illumination for LIF, LII, LIP and broadband
OAS possible.
- Thermal
CVD of SWNT, MWNT, and vertically aligned nanotube arrays (VANTAs)
on substrates
Several systems are available
for nanotube growth:
- CVD system in
a 3"-i.d. tube furnace
(1200°C) with pressures
down to ~ 1 torr and fast-acting electro-pneumatic
valves for switching source gases; integrated time-resolved
reflectivity
diagnostics
and remote video imaging of growth dynamics. The
system is in proximity of tunable ns-lasers for laser
diagnostics of
CVD processes,
or
for
combined laser-CVD (e.g. for doping of nanotubes
during CVD growth, or laser-generation of catalyst
nanoparticles for
CVD,
etc.).
- Thermal CVD of single and multiwall carbon
nanotubes, nanotube arrays, and nanotube patterns at atmospheric
pressure
and flow.
- Ferrocene-enhanced thermal CVD (atmospheric
pressure) growth of up to 1-cm long multiwall nanotube arrays
and
patterns. The system allows
real-time study of vertically aligned growth.
- Time-resolved
reflectivity (TRR) of aligned nanomaterial growth rates by
CVD
Utilizes stabilized HeNe laser beam reflectivity Fabry-Perot
interference oscillations and attenuation to directly measure
the height of vertically-aligned nanostructure
arrays during growth – for growth rate, catalyst assessment.
- Rapid thermal laser-CVD growth and processing
facility with X-Y-Z control
Utilizes 600W Nd:YAG
laser (either
broad beam
or focused to ~ 600 microns)
to laser-heat substrates rapidly for nanomaterial
synthesis or annealing under controlled pressure and flow, including
CVD gases.
Oxide
Heterostructure Pulsed-Laser Deposition with high-pressure RHEED
- Complex oxide heterostructure PLD
Complex
oxide film and superlattice growth by pulsed-laser
deposition (including magnetic, ferroelectric,
superconducting materials; strain-engineered heterostructures)
with in-situ high-pressure RHEED for atomic-layer
control.
- Complex heterostructures combining PLD, RF-sputtering, and laser heating
Growth of thin films of oxide and metallic compounds combining oxide PLD and RF sputtering to create composites and superlattice heterostructures. This growth system incorporates laser heating, and pressure control to rapidly change growth conditions, along with in-situ RHEED.
- Oxide Target Synthesis
Standard facilities
for milling, drying, pressing, and sintering of oxide
materials,
to prepare PLD
targets.
Laser/nanomaterial
processing
- Photolithographic-,
E-beam-, FIB-Patterning/Wiring of Nanomaterials for Devices
(Through the Nanofabrication Research Laboratory) Processing of nanomaterials
including spin-coating, dielectrophoretic deposition, etc. combined with photo-
and e-beam lithographic techniques and FIB electrode placement for the addressing
of nanomaterials as prototype devices.
- Laser/nanomaterial
interactions and X-Y-Z processing
High-power (500W) Nd:YAG (1064 nm) or low-power (30 mW) fs/ps addressable light
for laser-direct write, machining, and annealing of nanostructures and composites
under controlled atmospheres.
Wet/Dry Assembly of Organic/Inorganic/Metal Heterostructures
- Controlled atmosphere dual glove box evaporator system
An MBraun Labmaster double glove box system with integrated vacuum deposition chamber (Angstrom Amod e-beam and thermal evaporator) and spin coater (Specialty Coating Systems Model SCS G3) is available for physical vapor deposition of metals and small-molecule organics and for spin coating of polymers in a clean, inert environment. Thermal chambers have six sources, including two RADAK sources for small-molecule deposition with co-deposition capability, which enable multilayer deposition, gradient and doping film deposition at controlled substrate temperatures (RT to 400°C). The system is also equipped for computer-controlled e-beam deposition with four pocket electron-beam sources and two thermal sources for high melting point metals and inorganic compound thin film deposition. A 400°C vacuum oven is mounted to one end of the glove box. The system has various shadow masks for patterning electrodes for various organic electronic devices including OFETs, OLEDs, OPVs, and spin valves. The system enables the assembly of organic and inorganic multilayer thin films with Ångstrom thickness resolution for organic electronic devices.
- Sonospray deposition of nanomaterials and organics
Computer-controlled sono-spray deposition of nano materials, polymers, and nano composites from solutions and suspensions for uniform or patterned deposition on small or large areas (up to 1ft x 1ft) with minimum feature size of 1.5 mm. The system enables multilayer deposition on various substrates, including polymers, while controlling the substrate temperature (up to 180C). A micro-syringe pump feeds a solution allowing deposition from small (<10ml) ) volumes of solution and a dual-syringe configuration allows simultaneous deposition from two different solutions with variable ratio. The system is also equipped with a sono-syringe, to prevent precipitation of material during deposition (min required volume 20ml).
Electrical
Characterization of nanomaterials
- Semiconductor
parameter analyzer, cryogenic probe station, and both DC and
AC characterization systems.
- AC
impedance spectroscopy system based on the Zahner
analyzer IM6 supports
traditional electrochemical investigations like impedance measurements
(10 µHz-8 MHz, 10 Ohm-1 GOhm), cyclic voltammetry, corrosion,
current-potential curves, etc. with modeling software by THALES.
AC-amplitude range
1 mV to 1 V. Impedance range 10 mOhm to 1 GOhm (+/-1 dB)
- Special
configuration Zahner controlled intensity modulated photospectroscopy capability
enables dynamic photo-electric investigations including
mixed photo electric transfer functions on photo-sensitive
objects (e.g. photovoltaic materials).
Optoelectronic
Characterization of nanomaterials and composites
- Calibrated
OLED efficiency measurement system (including angular light distribution).
- Spectral
photo response and calibrated PV efficiency measurement system
- AC
impedance spectroscopy system (temperature controlled electro-optical
measurements).
- Intensity
modulated (LED based: UV-NIR) Photocurrent/Photovoltage measurement (solid, liquid samples).
- Optical
characterization (UV-NIR): absorbance, transmittance, reflectance
(diffuse and specular), PL, Raman under electrical
excitation.
Laser-based Spectroscopy of nanomaterials
- UV-VIS-NIR Characterization of SWNTs, etc. by Absorption
Spectroscopy
Measurement and analysis of optical absorption spectra to investigate
electronic energy levels and dispersion of solubilized nanomaterials.
- UV-VIS-NIR Fluorometry with remote fiber probing of liquids/surfaces
Utilizes dispersed Xe lamp to excite fluorescence of solubilized
or solid specimens. Two spectrometers (UV-VIS, and NIR) under computer
control record fluorescence spectra. Excitation wavelength can
be scanned
to provide complete fluorescence maps vs. excitation wavelength.
Fiber probe permits remote sampling of liquids or solid surfaces.
- Ultrafast laser spectroscopy of nanomaterials
and composites
Utilizing tunable fs/ps laser, and fs-amplified
systems (see
below) with white-light
continuum pump-probe spectroscopy. Set up includes a 250 mm optical delay line (sub micron resolution and repeatability), a ¼ meter spectrograph and CCD array.
- Raman characterization of
carbon nanotubes, oxides, polymers
Confocal micro-Raman
spectroscopy and assessment of SWNT diameters,
defect densities,
dispersion and alignment in composites, etc. using 2 fixed
wavelengths (785 nm, 633 nm) and 3-dim rotation/translation
stages.
- Tunable
Raman (micro/macro) spectroscopy (0.25 – 1.6 µm)
New system utilizing tunable ps laser coupled with high-resolution JY T-64000 monochromator to permit Raman spectroscopy at any wavelength (scattered wavelengths beyond 50 cm-1 of laser line). Also, tunable CW Ti:Sapphire laser for 780-950 nm excitation wavelengths. Inverted microscope with XY stage, and standard microscope with XY and piezo-Z stages.
- In
situ Raman spectroscopy at <1500°C: CVD, annealing,
electrochemistry
Linkam stage annealing and growth chamber permits in situ dynamics
of SWNT growth or processing under Raman microscope. Electrochemical
cell under Raman microscope.
- Tunable
(0.25 – 1.6 µm)
fs/ps laser system (nJ @ 80 MHz)
Ti:Sapphire-based oscillator coupled to second- and third-harmonic
generator crystals, along with OPO, may be run in either fs or
ps mode. Coupled to confocal microscope with XYZ control for
Raman spectroscopy or fluorescence measurements Provides nj/ps-pulse
at 80MHz to avoid damage to nanostructures.
- Tunable
(0.3 – 2.6 µm)
High energy, Ultrashort, fs laser system (2.5 mJ @ 1 kz, 40 fs)
Ti:Sapphire-based amplifier used to pump a high energy non-collinear
OPA (accepts > 2mJ/pulse). A portion of the fundamental beam (800
nm) is used to generate a white light supercontinuum for spectrally-resolved
pump-probe techniques. System also applicable to other nonlinear
spectroscopies or fs laser processing (ablation, annealing, machining,
polymerization, etc.).
- Tunable
(0.22 – 1.8 µm)
ns laser system (mJ @ 10Hz)
Tunable Nd:YAG –pumped
OPO laser provides high pulse energies for in situ spectroscopic
experiments (e.g. LIF) of nanomaterial growth
environments,
laser ablation synthesis, or nanomaterial luminescence.
Spectroelectrochemistry
- Spectroelectrochemical
Characterization of Nanomaterials and Composites
Combined electrochemical measurements during spectrophotometry. Investigations
of reduction-oxidation reactions; nA sensitivity using Faraday cage with three-electrode
stand.
Capabilities
provided by other CNMS groups
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