For over two decades, the Thin Films Laboratory (TFL) at the Hawaii Natural Energy Institute (HNEI) has been a leader in innovative material research and development for solar energy converter systems. Specifically, the TFL groundbreaking approach in material R&D allowed for a better understanding of the fundamental properties of numerous photovoltaic technologies, including amorphous silicon and polycrystalline copper-indium-gallium-diselenide (CIGSe) alloys. Aside from “conventional” PV systems, HNEI-TFL research activity also comprises the discovery of new photo-catalytic materials capable of direct conversion of sunlight into usable chemical energy, a.k.a. “Solar Fuels”, with focus on solar-driven water splitting for hydrogen production.
The Thin Films Lab is a unique facility at HNEI, situated with sophisticated state-of-the-art equipment for the fabrication of thin film materials and devices, including co-evaporation chambers, sputtering systems and plasma enhanced chemical vapor deposition devices.
The research team at TFL is also actively participating in the development of new low-cost synthesis protocols as a substitution to high temperature/vacuum based thin films deposition techniques. The recent introduction of chemistry in solar cell manufacturing was undoubtedly a game changer in material design and could potentially reduce cell production costs. After two decades of R&D in vacuum-based thin film material synthesis, HNEI TFL is now taking a step further toward chemical-based solar cell manufacturing.
PECVD System: MV-Systems dual-chamber high-vacuum "plasma enhanced chemical vapor deposition" system with load lock for depositing amorphous and microcrystalline silicon and germanium alloys. Applications include fabrication of photovoltaic materials and devices; and visible and infrared sensors.
CIGS Evaporation System: Varian 3125 diffusion-pumped multisource evaporator including five independently-controlled furnaces for elemental co-deposition of copper, indium, gallium, selenium and sodium. For fabrication of CISe and CIGSe photovoltaic materials and devices.>
Sputtering Deposition System: Perkin-Elmer 2400 turbomolecular-pumped three-gun co-sputtering system. Applications include: transparent conducting oxides; catalysts and other novel films; and refractory metal films.>
Metal Thermal Evaporation System: NRC 3117 diffusion-pumped four-source thermal evaporator for depositing metallic films and contact grids.>
CdS Film Deposition: Chemical bath system currently handling two 5 cm x 9 cm substrates. Expandable to a larger area.>
Semiconductor/Solar Cell Characterization Station: including high-precision electronic measurement equipment, temperature-controlled probe chuck, solar simulator and LED light sources. Measurement capabilities include:
- temperature-dependent light/dark JV characterization (pA resolution)
- temperature-dependent AC & DC conductivity measurement
- temperature-dependent CV measurement
- transient response characterizations (ns resolution)
Electrochemical Test Station: including high-precision electronic measurement equipment and Plexiglas fixtures for test- and reference-electrode mounting. Measurement capabilities include voltammetry and cyclic voltammetry (pA resolution), and long-term corrosion testing.
Quantum Efficiency System: MRG model QE1800 for measurement of photocollection in thin film devices in the 350 - 1800nm wavelength range.
UV-VIS Photospectrometer: Perkin-Elmer model Lambda 2 with integrating sphere: for optical transmission, reflection and absorption measurements of thin films.
Surface Profilometer: Tencor Alpha Step model 200 for thin-film thickness measurements.
Four-Point Probe Station: Signatone model S301-6: automated system for film resistivity measurements.
Gas Chromatograph: Varian with TCD/FID detectors.
Gas Chromatograph: Shimadzu GC14-A.
Surface Analysis at the University of Hawaii at Manoa
In addition to the HNEI equipment listed above, the UH campus boasts a wide range of sophisticated surface analysis techniques which are generally available on a recharge basis.
X-ray Diffraction System: Scintag model PAD V
Scanning Electron Microscope (Zeiss Model DSM-962) + EDX capability
High resolution Scanning Electron Microscope (Hitachi model S-800)
Fourier Transform Infrared Spectrometer: Thermo-Nicolet
Two Spex triplemate Raman instruments with C.C.D. detectors, computer controlled data acquisition system and micro Raman attachment
Advanced Confocal Microscope (Bio-Rad Micro-science Division)
Atomic Force Microscope (Nanoscope Instruments)
Scanning Tunneling Microscope (Nanoscope Instruments)
Ernst-Leitz Scanning Acoustic Microscope (ELSAM)
Sandercock six-pass tandem Brillouin scattering system
Fully automated ellipsometer (Auto-EL-III Rudolph Research)