Donor characterization in ZnO by thermally stimulated luminescence

Abstract

Low temperature thermo-luminescence (TL) was applied to measurements of the ionization energy of donors in ZnO. Three hydrogen-related donors were characterized with ionization energies of 36, 47 and 55 meV - values that are in complete agreement with previous reports. The donor types can be “switched” by relevant thermal treatments. These measurements also revealed the presence of two distinct sources for the green luminescence in ZnO. This work indicates that TL can be used to measure the donor energies in luminescent semiconductors. This approach can be particularly useful for thin-film investigations when the results of Hall-effect measurements are obscured by contributions from conductive interfaces or substrates.