摘要
Hydrogen is found to diffuse rapidly into ZnO from either a molecular (D2) gas source or from a D2 plasma at temperatures in the range of 100-200 °C. In samples deuterated from a plasma excited at 13.56 MHz, the incorporated deuterium concentration is saturated at 6× 1018 cm-3 throughout the entire 1.2 μm epi-ZnO thickness at 250 °C. This deuterium is stable against reverse bias application at 25 °C for 24 h. By sharp contrast, deuterium incorporated from exposure to D2 gas at 100 °C can be entirely removed by reverse (negative) bias application in a diode structure using a Pt contact on the n -type ZnO. These results are consistent with the state of the deuterium in the ZnO being a function of both the concentration and the flux during incorporation. At low concentrations, the deuterium is likely to be in a positively charged atomic form or bound in defects that are readily dissociated by an electric field, while at higher concentrations the deuterium may be in neutral states such as D2 or OH complexes. © 2007 American Institute of Physics.