Zn/sub 3/P/sup 2/ as an improved semiconductor for photovoltaic solar cells. Final report, September 1, 1978-March 31, 1982

Technical Report · Thu Apr 01 04:00:00 EST 1982

OSTI ID:5288832

The main emphasis was placed on the development of solar cells based on Zn/sub 3/P/sub 2/. Polycrystalline boules of Zn/sub 3/P/sub 2/ with grain size of the order of a few mm were doped with Ag to reduce the resistivity to 1 t0 ..cap omega..-cm. Single crystals of Zn/sub 3/P/sup 2/ were prepared by using a seed crystal. Thin polycrystalline films of Zn/sub 3/P/sub 2/ were deposited by close-spaced vapor transport on a variety of substrates. Schottky barrier devices, approx. = 1 cm/sup 2/ in area, were prepared by depositing a thin film of Mg. A maximum total area conversion efficiency of approx. = 6% on bulk Zn/sub 3/P/sub 2/ wafers and 4.3% on a thin film cell were achieved. An n/p junction was created as a result of Mg diffusion by heating Mg-Zn/sub 3/P/sub 2/ cells at 100/sup 0/C in air. The diffusion coefficient of Mg was determined. The activation energy of thermal diffusion of Mg atoms was found to be small (approx. = 0.4 eV), indicating that the Mg atoms occupy interstitial sites in the Zn/sub 3/P/sub 2/ lattice. A survey of semiconductor materials and their properties was made to select a suitable heterojunction partner for Zn/sub 3/P/sub 2//. Heterojunction devices were prepared by depositing thin n-type films of ZnO by rf sputtering and ZnS, CdS and ZnSe by vacuum evaporation. An active area conversion efficiency of approx. 2% was achieved on a ZnO/Zn/sub 3/P/sub 2/ heterojunction. A detailed analysis of the capacitance measurement showed that the V/sub oc/ was limited by a high density of interface states. The V/sub oc/ was higher for ZnSe-Zn/sub 3/P/sub 2/ heterojunctions but the light generated current was considerably lower. Experiments were conducted in synthesizing Cd/sub 3/P/sub 2/ and solid solutions of the type (Zn/sub 1-x/Cd/sub x/)/sub 3/P/sub 2/ with (0 less than or equal to x less than or equal to 1) and optical absorption measurements were made.

• Research Organization: Solar Energy Research Inst., Golden, CO (USA); Delaware Univ., Newark (USA). Inst. of Energy Conversion
• DOE Contract Number: AC02-77CH00178
• OSTI ID: 5288832
• Report Number(s): SERI/TR-8062-1-T16; ON: DE82016406
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
ALKALINE EARTH METAL COMPOUNDS
ALKALINE EARTH METALS
ALUMINIUM
CADMIUM COMPOUNDS
CADMIUM PHOSPHIDES
CHALCOGENIDES
CRYSTAL DOPING
CRYSTALS
DEPOSITION
DIFFUSION
DIRECT ENERGY CONVERTERS
EFFICIENCY
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
ENERGY GAP
EQUIPMENT
FABRICATION
FILMS
FUNCTIONS
HETEROJUNCTIONS
INORGANIC PHOSPHORS
JUNCTIONS
MAGNESIUM
MAGNESIUM COMPOUNDS
METALS
MONOCRYSTALS
OXIDES
OXYGEN COMPOUNDS
PHOSPHIDES
PHOSPHORS
PHOSPHORUS COMPOUNDS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
PNICTIDES
SCHOTTKY BARRIER SOLAR CELLS
SELENIDES
SELENIUM COMPOUNDS
SEMICONDUCTOR JUNCTIONS
SOLAR CELLS
SOLAR EQUIPMENT
SPECTRAL RESPONSE
SULFIDES
SULFUR COMPOUNDS
WORK FUNCTIONS
ZINC COMPOUNDS
ZINC OXIDES
ZINC PHOSPHIDE SOLAR CELLS
ZINC PHOSPHIDES
ZINC SELENIDES
ZINC SULFIDES