The influence of intrinsic defects and hydrogen-defect complexes on the properties of n-type ZnO crystals has been studied in terms of annealing and hydrogen plasma irradiation. Electrical and optical properties have been found to be dependent on annealing conditions and hydrogen plasma irradiation. When an as-polished sample was annealed in Ar atmosphere containing Zn vapor at 800°C for 2 h, the color of the sample changed into orange because of the formation of oxygen vacancies (VO). In spite of the VO formation, Hall mobility of the sample increased from 162 to 210 cm 2 V −1 s −1. Carrier concentration also increased by about four orders of magnitude. The simultaneous increases in carrier concentration and Hall mobility indicate that zinc vacancy (VZn) concentration, which acts as a compensation acceptor, are decreased by supplying Zn vapor during the annealing. Hydrogen plasma irradiation did not affect electrical properties of the sample annealed in Ar atmosphere containing Zn vapor, but improved those of the sample annealed in pure Ar atmosphere. The carrier concentration and Hall mobility increased by hydrogen plasma irradiation decreased with increasing post-annealing temperature. The post-annealing temperature dependence suggests that VZn passivated by hydrogen starts to dissociate at temperatures around 400°C.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.