Hydrogen effects on deep level defects in proton implanted Cu(In,Ga)Se-2 based thin films

Abstract

Hydrogen effects on deep level defects and a defect generation in proton implanted Cu(In,Ga)Se-2 (CIGS) based thin films for solar cell were investigated. CIGS films with a thickness of 3 mu m were grown on a soda-lime glass substrate by a co-evaporation method, and then were implanted with protons. To study deep level defects in the proton implanted CIGS films, deep level transient spectroscopy measurements on the CIGS-based solar cells were carried out, these measurements found 6 traps (including 3 hole traps and 3 electron traps). In the proton implanted CIGS films, the deep level defects, which are attributed to the recombination centers of the CIGS solar cell, were significantly reduced in intensity, while a deep level defect was generated around 0.28 eV above the valence band maximum. Therefore, we suggest that most deep level defects in CIGS films can be controlled by hydrogen effects. (C) 2012 Elsevier B.V. All rights reserved.