Development of Cu-doped ZnTe as a back-contact interface layer for thin-film CdS/CdTe solar cells

Journal Article · Wed May 01 00:00:00 EDT 1996 · Journal of Vacuum Science and Technology, A

DOI:https://doi.org/10.1116/1.580394· OSTI ID:288269

Gessert, T A; Mason, A R; Sheldon, P; Swartzlander, A B; Niles, D; Coutts, T J ^[1]

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1. 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 Laboratory
• DOE Contract Number: AC36-83CH10093
• OSTI ID: 288269
• Report Number(s): CONF-9510385--
• Journal Information: Journal of Vacuum Science and Technology, A, Journal Name: Journal of Vacuum Science and Technology, A Journal Issue: 3 Vol. 14; ISSN JVTAD6; ISSN 0734-2101
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BACK CONTACT SOLAR CELLS
CADMIUM SULFIDES
CADMIUM TELLURIDES
COPPER ADDITIONS
DIELECTRIC PROPERTIES
ELECTRIC CONDUCTIVITY
ELECTRIC CONTACTS
HEAT TREATMENTS
SPUTTERED MATERIALS
TEMPERATURE RANGE 0400-1000 K
THIN FILMS
ZINC TELLURIDES