Correlation between electrical, optical properties and Ag2+ centers of ZnO:Ag thin films

ZnO:Ag films have been fabricated on a n-Si (1 1 1) substrate and then annealed in situ in an O-2 ambient, using Ag2O as a silver dopant by pulsed laser deposition. Hall measurements reveal that the films prepared at 400 and 450 degrees C show p-type behavior with a hole concentration of 6.3 x 10(16)-1.2 x 10(17)cm(-3) and a mobility of 2.48-3.30cm(2)/Vs. By combining Hall measurements, electron paramagnetic resonance (EPR) signals, and photoluminescence (PL) spectra, a correlation is observed between the free hole carriers, the Ag2+ centers, and the neutral acceptor bound excitons. Additionally, the p-ZnO:Ag/n-Si heterojunction shows a diode-like I-V characteristic. (c) 2007 Elsevier B.V. All rights reserved.