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Title: Zn/sub 3/P/sub 2/ as an improved semiconductor for photovoltaic solar cells. Thirteenth quarterly report, September 1, 1981-November 30, 1981

Technical Report ·
OSTI ID:5288947

Efforts to produce bulk n-type Zn/sub 3/P/sub 2/ by incorporating Mg as an impurity have so far resulted in high resistivity p-type material. On the basis of the capacitance voltage characteristics of Mg diffused Zn/sub 3/P/sub 2/ devices, a model in which Mg compensates the acceptor levels, creating a thin insulating region near the surface, was developed. In order to test the validity of this model, the thickness of the Mg diffused layer was measured by first heating a Mg/Zn/sub 3/P/sub 2/ device to produce approx. 50 ..mu..m thick Mg diffused layer and then measuring the device characteristics after successively removing a few ..mu..m of the surface at a time. This experiment confirmed the results reported earlier on the basis on n/p junction formation. A study of the native oxide of Zn/sub 3/P/sub 2/ produced by thermal oxidation was conducted for the development of MIS solar cells. The oxidized surface was composed of ZnO and P/sub 2/O/sub 5/ and was found to contain excess zinc. The as-grown oxide layer in Zn/sub 3/P/sub 2/ was electrically conducting and, therefore, not suitable for MIS cells. MIS cells produced by plasma oxidation of Zn/sub 3/P/sub 2/ had V/sub oc/ approx. 0.5 Volts and J/sub 0/ approx. 10/sup -9/ Amp/cm/sup 2/. A software package to store, sort and retrieve the data generated by the production and testing of Zn/sub 3/P/sub 2/ thin-film cells was developed. ZnSe/Zn/sub 3/P/sub 2/ heterojunction devices prepared by vacuum evaporation of ZnSe had a maximum V/sub oc/ of 0.36 Volts and J/sub sc/ in the range of 0.1 and 0.7 mA/cm/sup 2/. The resistivity of ZnSe films was lowered by annealing in the presence of zinc vapor at 400/sup 0/C. Al doping in ZnSe gave very leaky diodes and a lower V/sub oc/. Optical absorption measurements were made on thin ZnSe films deposited on glass by vacuum evaporation and close-spaced vapor transport.

Research Organization:
Solar Energy Research Inst., Golden, CO (USA); Delaware Univ., Newark (USA). Inst. of Energy Conversion
DOE Contract Number:
AC02-77CH00178
OSTI ID:
5288947
Report Number(s):
SERI/PR-8062-1-T15; ON: DE82014367
Resource Relation:
Other Information: Portions of document are illegible
Country of Publication:
United States
Language:
English