The detailed microstructural characterization of CuInS₂ (CIS) polycrystalline films is performed by combined in depth MicroRaman scattering/Auger Electron Spectroscopy measurements as a function of the chemical composition and temperature of processing. This has allowed to identify the main secondary phases in the layers as CuIn₅S₈ for Cu-poor samples and CuS for Cu-rich ones. The presence of such phases is strongly related to the temperature of processing, being secondary phase formation inhibited when the growing temperature decreases from 520°C to 370°C. This is also accompanied by a significant degradation of the structural CIS features, as reflected by the increase in both shift and broadening of the A₁ CIS mode in the spectra, and by the decrease of the grain size estimated by cross-section TEM. Besides, Raman spectra measured from samples grown at lower temperatures are characterized by the presence of an additional mode at about 305 cm^-1. The presence of this mode in the spectra from Cu-rich samples gives experimental support to its previously proposed structural origin. Finally, MoS₂ secondary phase has also been identified at the CIS/Mo interface region, being its occurrence also inhibited at low growing temperatures.

Date Published: 1 April 2003
PDF: 11 pages
Proc. SPIE 5024, Selected Papers on Optics and Photonics: Optical Diagnostics of Materials and Devices for Opto-, Micro-, and Quantum Electronics, (1 April 2003); doi: 10.1117/12.497250

Published in SPIE Proceedings Vol. 5024:
Selected Papers on Optics and Photonics: Optical Diagnostics of Materials and Devices for Opto-, Micro-, and Quantum Electronics
Sergey V. Svechnikov; Mikhail Ya. Valakh, Editor(s)