High-efficiency, large-area GaAs solar cells

Conference · Tue May 01 04:00:00 EDT 1984 · Conf. Rec. IEEE Photovoltaic Spec. Conf.; (United States)

OSTI ID:5123185

Werthen, J G; Ford, C F; Humaker, H C

High-efficiency, 4-cm/sup 2/ GaAs solar cells have been fabricated by metalorganic chemical vapor deposition (MOCVD). Efficiencies as high as 18.7% for p-n and 18.4% for n-p structures have been measured. The use of MOCVD allows the deposition of extremely well-defined layers and its flexibility can accommodate both p-n and n-p junctions. Prior to any growths, computer simulations were carried out to optimize cell performance. The computer model has been constantly updated with measured values of mobilities, minority carrier diffusion lengths, and absorption constants which are then used to solve the transport equations and optimize efficiency. The model predicts optimum layer thicknesses, doping levels, grid pattern and AR coating. Both p-n and n-p GaAs cells were grown on n- and p-type substrates, respectively. All cell configurations include an AlGaAs (90% Al) window to reduce surface recombination in the topmost active layer. A highlydoped contact layer is finally grown on top of the window layer to enable formation of good ohmic contacts and provide protection of the cell during processing. The contact layer is selectively etched away after metallization, and the briefly exposed window layer is covered with a single-layer Si/sub 3/N/sub 4/ AR coating. A standard grid configuration for 2-cm x 2-cm Si space cells was used and the cell metallization was plated up to 3-..mu.. thickness.

• Research Organization: Varian Associates, Inc., Solid State Laboratory, Palo Alto, CA
• OSTI ID: 5123185
• Report Number(s): CONF-840561-
• Conference Information: Journal Name: Conf. Rec. IEEE Photovoltaic Spec. Conf.; (United States)
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
ARSENIC COMPOUNDS
ARSENIDES
CHEMICAL COATING
CHEMICAL VAPOR DEPOSITION
COMPUTERIZED SIMULATION
DEPOSITION
DIRECT ENERGY CONVERTERS
EFFICIENCY
EQUIPMENT
FABRICATION
GALLIUM ARSENIDE SOLAR CELLS
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
JUNCTIONS
MATERIALS
N-TYPE CONDUCTORS
P-N JUNCTIONS
P-TYPE CONDUCTORS
PERFORMANCE
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PNICTIDES
SEMICONDUCTOR JUNCTIONS
SEMICONDUCTOR MATERIALS
SIMULATION
SOLAR CELLS
SOLAR EQUIPMENT
SURFACE COATING