Effects of annealing on structural and electrical properties of sub-micron thick CIGS films

Abstract

In this study, we have investigated the electrical and structural properties of sub-micron thick Cu(In,Ga) Se2 (CIGS) films with various in-situ post annealing times. Sub-micron thick CIGS films were deposited on Mo/soda-lime glass (SLG) substrates by single-stage co-evaporation. We decreased the deposition time to 700 s for sub-micron thick CIGS films (≈0.85 μm thickness). After deposition, the CIGS films were annealed under a constant Se rate by a SiC heater for 500-3000 s in a co-evaporator. Increased annealing time led to improved surface morphology and grain size. In the XRD patterns, the CIGS films also showed improved crystal quality for the (112) plane. We suggest that post annealing of sub-micron thick CIGS films at optimized time can be applied for improving device efficiency. The open circuit voltage (Voc) and the fill factor (FF) were increased by 15% and 10%, respectively. The total cell efficiency was increased by more than 35%. © 2013 Elsevier B.V. All rights reserved.