Fermi level-dependent defect formation at Cu In,Ga/Se interfaces

A removal of Cu from the surface is observed when the Fermi level moves upwards in the bandgap of Cu In,Ga.Se2 semiconductors during contact formation. A model based on a comparison of band edge energies and electrochemical redox energies is proposed, which qualitatively explains the observations and might be used as a simple rule for predicting similar defect formation processes. q2000 Elsevier Science B.V. All rights reserved.