Full text loading...
characteristics for remote plasma-exposed and unexposed E–P samples. (a) exposure of the surface produces a SB of with an ideality for the lower grade material. (b) The same transition occurs for a exposed sample of higher quality with a calculated SB height of and , however, a exposure indicates an ohmic behavior. (c) Higher-quality (0001) surfaces change from ohmic to rectifying after plasma treatment with SB and ideality.
XPS results before and after 20% He plasma treatment (low grade E–P sample). (a) Plasma treatment removes the (deconvolved) OH peak and shifts the peak rigidly by , as well as the peak in (b), indicating -type band bending. (c) The peak disappears after plasma treatment, leaving only a Zn Auger shoulder, indicating removal of adsorbed carbon.
CL spectra for treated and untreated E–P samples of a lower grade. (a) Relative CL intensity for the (green) emission, often attributed to oxygen vacancies, decreases with increasing electron-beam energy. All spectra are normalized to NBE. (b) The integrated peak intensity ratio (GD∕NBE) vs electron-beam energy indicates a factor of 2 increase in GD defect concentration within of the surface. After a exposure, the intensity decreases by 50%, indicating GD partial removal or passivation.
Photoluminescence spectra taken at in the bound exciton region for the polar ZnO high grade E–P surface. The line attributed to hydrogen as a shallow donor in ZnO is significantly reduced after a plasma exposure.
Article metrics loading...