Homoepitaxial growth of reduced donor concentration ZnO films exhibiting atomically smooth surface is demonstrated by helicon-wave-excited-plasma sputtering epitaxy. Using a crystalline ZnO target prepared by hydrothermal method, concentrations of B, C, Cr, Li, and Si in the films underran the detection limits of secondary-ion-mass spectrometry. Consequently, low temperature photoluminescence spectra were dominated by sharp emission peaks originating from the recombination of excitons bound to a neutral Al donor, of which concentration was 2 × 1016cm-3. Nonradiative lifetime dominated the recombination process above 50K, which is most likely due to the presence of lifetime killers such as Ni and Fe.
ASJC Scopus subject areas
- Physics and Astronomy(all)