Structural and luminescent properties of Er-doped ZnO films grown by metalorganic chemical vapor deposition

Structural and luminescent properties of Er-doped ZnO (ZnO:Er) grown by metalorganic chemical vapor deposition were investigated. In comparison to the undoped ZnO, the c-axis crystallographic orientation was deteriorated and the photoluminescence (PL) intensity of the band-edge became lower in the ZnO:Er. The weak band-edge PL in the ZnO:Er was due to the nonradiative recombination centers induced by the Er-doping processes. The band-edge PL intensity of ZnO:Er was drastically increased by the temperature annealing at 800°C in O2 ambient. The annealed ZnO:Er showed clear 1.54μm PL originating from the I13∕24→I15∕24 transitions of the Er3+ ions. These PL properties showed that the local arrangement of the Er ions was changed by the thermal annealing, resulting in a transformation from Er-related nonradiative centers in the as-grown sample to luminescent centers for 1.54μm PL in the annealed one.