Nitrogen and hydrogen in bulk single-crystal ZnO

Zinc oxide (ZnO) is a wide band gap II–VI semiconductor with optical, electronic, and mechanical applications. Nitrogen is a promising acceptor dopant. Nitrogen–hydrogen (N–H) complexes were introduced into ZnO during chemical vapor transport (CVT) growth, using ammonia as a doping source. The N–H bond-stretching mode gives rise to an infrared (IR) absorption peak at 3151 cm 1 at liquidhelium temperatures. Along with passivating acceptors, hydrogen also acts as a shallow donor. In the previous work, we observed an IR peak at 3326 cm 1 that corresponds to a hydrogen donor. It is possible that this donor is actually a Ca-OH complex. & 2009 Elsevier B.V. All rights reserved.