Room temperature electroluminescence from the n-ZnMgO/ZnO/p-ZnMgO heterojunction device grown by ultrasonic spray pyrolysis

The heterojunction light-emitting diode with n-Zn0.8Mg0.2O/ZnO/p-Zn0.8Mg0.2O structure was grown on single-crystal GaAs(1 0 0) substrate by a simple process of ultrasonic spray pyrolysis. The p-type Zn0.8Mg0.2O layer was obtained by N–In codoping. A distinct visible electroluminescence with a dominant emission peak centered at ∼450 nm was observed at room temperature from the heterojunction structure under forward bias conditions. The origin of electroluminescence emission was supposed to be attributed to a radiative recombination through deep-level defects in the ZnO active layer. The result reported here provides convincing evidence that ZnO based light-emitting devices can be realized at extremely low cost.