On the nature of hydrogen-related shallow donors in ZnO

Vapor-phase grown ZnO samples treated with hydrogen plasma were studied by means of photoconductivity and IR absorption spectroscopy. Three bands at 180, 240, and 310cm(-1) were observed in the photoconductivity spectra of hydrogenated ZnO. These are identified as electronic transitions of three independent hydrogen-related shallow donors. Two electronic transitions from the H-I defect previously associated with the bond-centered hydrogen were found in IR absorption spectra at 1430 and 1480cm(-1). Based on the energies of these transitions H-I was ruled out as a candidate for the hydrogen-related shallow donor in ZnO. (c) 2005 Elsevier B.V. All rights reserved.