High-Vacuum Evaporation of n-CuIn3Se5 Photoabsorber Films for Hybrid PV Structures

Abstract

Thin films of Cu-In-Se (CISe) photoabsorber with an overall composition of CuIn3Se5 were deposited onto glass/indium tin oxide (ITO) substrates from a polycrystalline bulk CuIn3Se5 source using the high-vacuum evaporation technique. Thermal conditions for the substrates during the evaporation process and the subsequent annealing in vacuum were selected to prepare polycrystalline n-CuIn3Se5 photoabsorber layers for use in hybrid photovoltaic structures based on an inorganic photoabsorber and conductive polymer functional layers. The CISe layers were deposited at a substrate temperature of 200°C and were annealed at temperatures from 300°C to 500°C in vacuum. Part of the as-deposited CISe was annealed twice, in argon and in vacuum at 500°C. These layers exhibited high photosensitivity and photoconductivity when illuminated with white light at an intensity of 100 mW/cm2. The results showed that the chalcopyrite structure of the prepared CISe photoabsorber films adhered well to the glass/ITO substrate. The average value of charge carrier concentration and the profile of charge carrier concentration in the annealed CISe photoabsorber layer were calculated using impedance spectroscopy.