Photoelectronic properties of zinc phosphide crystals, films, and heterojunctions. Quarterly progress report No. 11, October 1-December 31, 1981
Variations in crystal growth techniques are continuing with the goal of: (1) improving single crystal quality; and (2) producing variations in crystal properties by doping and post-growth variations of stoichiometry. DLTS measurements using Mg/Zn/sub 3/P/sub 2/ Schottky diodes gave information on three deep levels between 0.55 and 0.66 eV above the valence band in sublimation grown crystals with densities in the 10/sup 15/ to 10/sup 16/ cm/sup -3/ range, and a shallower level at 0.12 eV with a density of 10/sup 15/ cm/sup -3/ in an iodine-transport grown crystal. Investigation of surface properties of Zn/sub 3/P/sub 2/ indicate that a Br-MeOH etch leaves a Zn-rich surface for both sublimation-grown and iodine-transport grown crystals. Detailed measurements were made on thick Mg/Zn/sub 3/P/sub 2/ junctions on sublimation-grown and iodine-transport grown crystals of log J-V characteristics as a function of temperature, for crystal substrates as etched, and after heat treatment in hydrogen at several temperatures. A systematic change in the junction transport mechanism from tunneling at heat-treatment temperatures less than 300/sup 0/C to recombination/generation for heat-treatment temperatures between 300 and 500/sup 0/C was found for Zn/sub 3/P/sub 2/ crystals grown by both growth techniques. A simple model involving a depletion of free carrier density near the surface as a result of heat treatment in hydrogen is proposed. Thin film Mg/Zn/sub 3/P/sub 2/ cells showed log J-V characteristics that are strongly light dependent, indicating an increase in tunneling with illumination. Evidence that the barrier height of the Mg/Zn/sub 3/P/sub 2/ junction is actually of the order of 0.9 to 1.0 eV was obtained. Attempts to prepare ITO/Zn/sub 3/P/sub 2/ junctions by electron-beam evaporation of ITO on single crystal substrates yielded poor diodes and negligible photovoltaic behavior.
- Research Organization:
- Solar Energy Research Inst. (SERI), Golden, CO (United States); Stanford Univ., CA (USA). Dept. of Materials Science and Engineering
- DOE Contract Number:
- AC02-77CH00178
- OSTI ID:
- 5664191
- Report Number(s):
- SERI/PR-1202-1-T3; ON: DE82011140
- Country of Publication:
- United States
- Language:
- English
Similar Records
Photoelectronic properties of zinc phosphide crystals, films and heterojunctions. Quarterly progress report No. 7, October 1-December 31, 1980
Photoelectronic properties of zinc phosphide crystals, films and heterojunctions. Quarterly progress report No. 5, April 1-June 30, 1980
Related Subjects
ZINC PHOSPHIDE SOLAR CELLS
ELECTRICAL PROPERTIES
ZINC PHOSPHIDES
CRYSTAL GROWTH
HETEROJUNCTIONS
SCHOTTKY BARRIER DIODES
TUNNEL EFFECT
BAND THEORY
CARRIER DENSITY
CRYSTAL DOPING
ELECTRIC CURRENTS
ELECTRIC POTENTIAL
ENERGY BEAM DEPOSITION
ENERGY LEVELS
ETCHING
HEAT TREATMENTS
HYDROGEN
INDIUM OXIDES
MAGNESIUM
MONOCRYSTALS
RECOMBINATION
SEMICONDUCTOR JUNCTIONS
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
TIN OXIDES
TRAPS
ALKALINE EARTH METALS
CHALCOGENIDES
CRYSTALS
CURRENTS
DEPOSITION
DIRECT ENERGY CONVERTERS
ELEMENTS
EQUIPMENT
INDIUM COMPOUNDS
JUNCTIONS
METALS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHOSPHIDES
PHOSPHORUS COMPOUNDS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
PNICTIDES
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
SOLAR CELLS
SOLAR EQUIPMENT
SURFACE COATING
SURFACE FINISHING
TIN COMPOUNDS
ZINC COMPOUNDS
140501* - Solar Energy Conversion- Photovoltaic Conversion