Optical properties and defect levels in a surface layer found on CuInSe{sub 2} thin films

Book · Sun Sep 01 04:00:00 EDT 1996

OSTI ID:276844

Abulfotuh, F; Wangensteen, T; Ahrenkiel, R; Kazmerski, L L ^[1]

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1. National Renewable Energy Lab., Golden, CO (United States)

In this paper the authors have used photoluminescence (PL) and wavelength scanning ellipsometry (WSE) to clarify the relationship among the electro-optical properties of copper indium diselenide (CIS) thin films, the type and origin of dominant defect states, and device performance. The PL study has revealed several shallow acceptor and donor levels dominating the semiconductor. PL emission from points at different depths from the surface of the CIS sample has been obtained by changing the angle of incidence of the excitation laser beam. The resulting data were used to determine the dominant defect states as a function of composition gradient at the surface of the chalcopyrite compound. The significance of this type of measurement is that it allowed the detection of a very thin layer with a larger bandgap (1.15--1.26 eV) than the CIS present on the surface of the CIS thin films. The presence of this layer has been correlated by several groups to improve the CIS cell performance. An important need that results from detecting this layer on the surface of the CIS semiconductor is the determination of its thickness and optical constants (n, k) as a function of wavelength. The thickness of this surface layer is about 500 {angstrom}.

• DOE Contract Number: AC36-83CH10093
• OSTI ID: 276844
• Report Number(s): CONF-960513--
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
COPPER SELENIDE SOLAR CELLS
COPPER SELENIDES
CRYSTAL DEFECTS
ELLIPSOMETRY
EXPERIMENTAL DATA
INDIUM SELENIDE SOLAR CELLS
INDIUM SELENIDES
OPTICAL PROPERTIES
PERFORMANCE
QUANTUM EFFICIENCY