Two to six compound thin films by MOCVD for tandem solar cells

Miscellaneous · Wed Jan 01 00:00:00 EST 1992

OSTI ID:6806256

Britt, J S

Polycrystalline Cd(1-x)Zn(x)S and Hg(x)Zn(1-x)Te films have been deposited on a variety of substrates by MOCVD. Deposition conditions have been adjusted based on measurements of the material properties. Heterojunction solar cells have been formed from these materials and their potential application as the upper member of a tandem solar cell has been examined. The evaluation and optimization of a high efficiency CdTe/CdS solar cell has also been accomplished. Polycrystalline Cd(1-x)Zn(x)S films were deposited at 350-425 C by the reaction between DMCd, DEZn, and the novel source, propanethiol (PM) in a H2 flow. The growth rate and bandgap energy are strongly dependent on the growth temperature, DMCd/DEZn molar ratio, and the II/VI molar ratio. TMAl and octyl-chloride have been introduced into the reaction mixture to lower resistivities to values suitable for device operation. Polycrystalline ZnTe films have been deposited at 270-400 C by the reaction between DIPTe and DMZn or DEZn in a H2 flow. ZnTe films have been deposited by photoenhanced and conventional MOCVD. Polycrystalline Hg(x)Zn(1-x)Te films have been deposited at 350-410 C by the reaction between elemental Hg, DIPTe, and DMZn in a H2 flow. AsH3 was introduced to the reaction mixture to control the resistivity. Heterojunctions have been formed with Cd(1-x)Zn(x)S and ZnSe. A technique for the formation of low-resistance contacts to CdTe with HgTe has also been developed. A pre-deposition heat treatment of CdS in H2 has been demonstrated beneficial to the photovoltaic characteristics of the junction. A post-deposition CdCl2 treatment has been shown to have a profound influence on the electrical characteristics of CSS CdTe/CdS junctions. The identification of optical losses in CSS CdTe/CdS solar cells has been helpful in improving efficiences.

• Research Organization: Univ. of South Florida, Tampa, FL (United States)
• OSTI ID: 6806256
• Resource Relation: Other Information: Ph.D. Thesis
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
HETEROJUNCTIONS
EVALUATION
OPTIMIZATION
SOLAR CELLS
EFFICIENCY
THIN FILMS
CHEMICAL VAPOR DEPOSITION
CADMIUM SULFIDES
CADMIUM TELLURIDES
DEPOSITION
ENERGY GAP
GROWTH
LOSSES
MATERIALS
MERCURY TELLURIDES
POLYCRYSTALS
SEMICONDUCTOR DEVICES
SUBSTRATES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0400-1000 K
ZINC SULFIDES
ZINC TELLURIDES
CADMIUM COMPOUNDS
CHALCOGENIDES
CHEMICAL COATING
CRYSTALS
DIRECT ENERGY CONVERTERS
EQUIPMENT
FILMS
INORGANIC PHOSPHORS
JUNCTIONS
MERCURY COMPOUNDS
PHOSPHORS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
SEMICONDUCTOR JUNCTIONS
SOLAR EQUIPMENT
SULFIDES
SULFUR COMPOUNDS
SURFACE COATING
TELLURIDES
TELLURIUM COMPOUNDS
TEMPERATURE RANGE
ZINC COMPOUNDS
140501* - Solar Energy Conversion- Photovoltaic Conversion