Development of Cu-doped ZnTe as a back-contact interface layer for thin-film CdS/CdTe solar cells
- National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)
The full potential of thin-film, CdS/CdTe photovoltaic solar cells will not be realized until issues relating to the fabrication of environmentally stable, low-resistance, and easily manufactured contacts to the {ital p}-CdTe layer are addressed. One alternative that provides the required contact parameters employs a Cu-doped ZnTe(ZnTe:Cu) interface layer between the {ital p}-CdTe and the outer metal contact. Thin films of ZnTe:Cu containing various concentrations of metallic Cu are produced by rf-magnetron sputtering. Additionally, the effect of incorporating small amounts of excess Zn into the sputtering target is studied. We find that the electrical resistivity of ZnTe:Cu films deposited at 300{degree}C, and prepared with Cu concentrations of {approximately}0.45 at.{percent}, is much higher than would be expected from studies of films doped with higher Cu concentrations ({approximately}6 at.{percent} Cu). We also find that postdeposition heat treatment significantly reduces the electrical resistivity of the films containing {approximately}0.45 at.{percent} Cu. However, compositional analysis indicates that the surface of the films become increasingly enriched in Zn at annealing temperatures {approx_gt}350{degree}C. Analysis of the hole effective mass ({ital m}{sub {ital h}}) for films containing {approximately}6 at.{percent} Cu indicates a value for {ital m}{sub {ital h}} of 0.35 {ital m}{sub {ital e}}, and a high-frequency dielectric constant ({var_epsilon}{sub {infinity}}) of 8.2.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- DOE Contract Number:
- AC36-83CH10093
- OSTI ID:
- 288269
- Report Number(s):
- CONF-9510385-; ISSN 0734-2101; TRN: 96:021858
- Journal Information:
- Journal of Vacuum Science and Technology, A, Vol. 14, Issue 3; Conference: 42. national symposium of the American Vacuum Society, Mineapolis, MI (United States), 16-20 Oct 1995; Other Information: PBD: May 1996
- Country of Publication:
- United States
- Language:
- English
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