Direct comparison of photoluminescence lifetime and defect densities in ZnO epilayers studied by time-resolved photoluminescence and slow positron annihilation techniques

摘要: The roles of point defects and defect complexes governing nonradiative processes in ZnO epilayers were studied using time-resolved photoluminescence (PL) slow positron annihilation measurements. density or size Zn vacancies (V ) decreased the PL lifetime (τ nr increased with higher growth temperature for grown on a ScAlMgO 4 substrate. Accordingly, steady-state free excitonic intensity increase τ at room temperature. use homoepitaxial substrate further V concentration. However, no perfect relation between other scattering centers was found. results indicated that recombination are governed not solely by single defects, but certain species introduced presence such as vacancy complexes.