Structural, electrical and optical properties of CuGaTe₂ absorber for thin‐film solar cells

Abstract

Near‐stoichiometry composition CuGaTe2 (CGT) thin films prepared by close‐spaced vapour transport (CSVT) with copper excess in the source has been investigated and was confirmed by energy dispersive spectroscopy. The influence of temperature substrate on structural properties of CGT was studied, with the optimal substrate temperature at 480 °C. Morphological and structural analyses allowed identifying the type of crystallites. Crystalline phases of the films were examined using X‐ray diffraction. A strong (112) orientation perpendicular to substrate plane was observed and additional reflections planes were also detected. The electrical resistivity was determined using the four probe method and lies in the 0.127‐0.271 Ω cm range. The direct bandgap is about 1.7 eV and resistivity showed a low value. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)