Er-doped ZnO films grown by pulsed e-beam deposition

Erbium (Er)-doped ZnO thin films were grown on fused silica (SiO2) substrates by pulsed electron-beam deposition (PED) and analysed by Rutherford backscattering spectrometry (RBS), ultraviolet-visible absorption, and photoluminescence (PL). Subsequent annealing at 700 deg. C produces remarkable effects on the optical properties of Er-doped films. Under 325 nm excitation, a dramatic increase of deep-level emission from 450 to 680 nm was observed from annealed Er-doped ZnO films. Under 488 nm excitation, the PL spectrum of annealed Er-doped ZnO films revealed sharp and well-resolved Stark-splitting peaks in both the green emission of 4S3/2 →4I15/2 transition and the red emission of 4F9/2→4I15/2 transition of Er3+ ions, which suggests that the Er ions have been incorporated inside the crystalline ZnO grains after thermal annealing