High efficiency cadmium telluride and zinc telluride based thin-film solar cells. Annual subcontract report, 1 March 1990--28 February 1992

Technical Report · Thu Oct 01 04:00:00 EDT 1992

DOI:https://doi.org/10.2172/10179966· OSTI ID:10179966

Rohatgi, A; Sudharsanan, R; Ringel, S A; Chou, H C ^[1]

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1. Georgia Inst. of Tech., Atlanta, GA (United States)

This report describes work to improve the basic understanding of CdTe and ZnTe alloys by growing and characterizing these films along with cell fabrication. The major objective was to develop wide-band-gap (1.6--1.8 eV) material for the top cell, along with compatible window material and transparent ohmic contacts, so that a cascade cell design can be optimized. Front-wall solar cells were fabricated with a glass/SnO{sub 2}/CdS window, where the CdS film is thin to maximize transmission and current. Wide-band-gap absorber films (E{sub g} = 1.75 eV) were grown by molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD) techniques, which provided excellent control for tailoring the film composition and properties. CdZnTe films were grown by both MBE and MOCVD. All the as-grown films were characterized by several techniques (surface photovoltage spectroscopy, Auger electron spectroscopy (AES), and x-ray photoelectron spectroscopy (XPS)) for composition, bulk uniformity, thickness, and film and interface quality. Front-wall-type solar cells were fabricated in collaboration with Ametek Materials Research Laboratory using CdTe and CdZnTe polycrystalline absorber films. The effects of processing on ternary film were studied by AES and XPS coupled with capacitance voltage and current voltage measurements as a function of temperature. Bias-dependent spectral response and electrical measurements were used to test some models in order to identify and quantify dominant loss mechanisms.

• Research Organization: National Renewable Energy Lab., Golden, CO (United States); Georgia Inst. of Tech., Atlanta, GA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC02-83CH10093
• OSTI ID: 10179966
• Report Number(s): NREL/TP--451-4999; ON: DE92016403
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501
36 MATERIALS SCIENCE
360601
AUGER ELECTRON SPECTROSCOPY
CADMIUM SULFIDE SOLAR CELLS
CADMIUM TELLURIDE SOLAR CELLS
CHEMICAL VAPOR DEPOSITION
ELECTRICAL PROPERTIES
FABRICATION
MOLECULAR BEAM EPITAXY
PHOTOELECTRON SPECTROSCOPY
PHOTOVOLTAIC CONVERSION
PREPARATION AND MANUFACTURE
PROGRESS REPORT
RESEARCH PROGRAMS
TEMPERATURE DEPENDENCE
THIN FILMS
ZINC TELLURIDES