Effects of substrate temperature and film thickness on properties of CuIn3Te5 thin films and solar cells

Abstract

The effects of substrate temperature (Tsub) and film thickness (dCIT) on the properties of CuIn3Te5 thin films and solar cells were investigated. CuIn3Te5 thin films (dCIT = 1.8–4.0 μm) were grown on both bare and Mo-coated soda-lime glass substrates at Tsub of 250–400 °C by single-step co-evaporation using a molecular beam epitaxy system. The microstructural properties were examined using scanning electron microscopy and x-ray diffraction. Well-developed (112)-oriented CuIn3Te5 grains were obtained by increasing the dCIT for Tsub of 250 °C. Cathodoluminescence analysis and temperature-dependent Hall measurements indicate the formation of shallow defect levels in the CuIn3Te5 films grown at higher Tsub. An optimum solar cell fabricated using CuIn3Te5 thin films (Tsub = 250 °C, and dCIT = 4.0 μm) yielded a total area (0.504 cm2) efficiency of 6.28%. Recombination mechanisms in the CdS/CuIn3Te5 thin-film solar cells are discussed on the basis of the temperature-dependent electrical properties of the films and solar cells.