Synthesis of SWNT’s, NT Arrays, graphene, 2D materials, NW’s, NP’s or thin films by CVD, Laser Vaporization, and PLD with in situ diagnostics
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.
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.
CVD of SWNT, MWNT, vertically aligned nanotube arrays (VANTAs), graphene, 2D materials,
Several CVD systems are available:
- 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.
reflectivity (TRR) of aligned nanomaterial growth rates by
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.
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.
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
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
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.
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.
situ Raman spectroscopy at <1500°C: CVD, annealing,
Linkam stage annealing and growth chamber permits in situ dynamics of SWNT growth or processing under Raman microscope. Electrochemical cell under Raman microscope.
(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.
(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.).
(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.
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
- Nanomaterials Synthesis and Functional Assembly (Polymers)
- Nanomaterials Theory Institute
- Imaging and Nanoscale Characterization
- Nanomaterials Synthesis and Functional Assembly (Optoelectronics)
- Nanomaterials Synthesis and Functional Assembly (Catalysis)
- Microscopy, Neutron and X-Ray Scattering Capabilities
- General Characterization Facilities
- Collaborating Facilities