Unambiguous identification of nitrogen-hydrogen complexes in ZnO

Zinc oxide (ZnO) is a wide-band-gap semiconductor with a range of potential applications in optoelectronics. The lack of reliable p-type doping, however, has prevented it from competing with other semiconductors such as GaN. In this Brief Report, we report the successful incorporation of nitrogen-hydrogen (N-H) complexes in ZnO during chemical vapor transport growth, using ammonia as an ambient. The N-H bond-stretching mode gives rise to an infrared absorption peak at 3150.6 cm(-1). Substitutions of deuterium for hydrogen and N-15 for N-14 result in the expected frequency shifts, thereby providing an unambiguous identification of these complexes. The N-H complexes are stable up to similar to 700 degrees C. The introduction of neutral N-H complexes could prove useful in achieving reliable p-type conductivity in ZnO.