Synthesis and defect-related emission of ZnO based light emitting device with homo- and heterostructure

To realize practical application of short-wavelength optoelectronic devices (such as light emitting diodes, LEDs, and LDs) based on ZnO materials, electroluminescence (EL) from ZnO based junction device is pivotal. In this article, ZnO based devices with different structures were grown on single-crystal GaAs(1 0 0) substrate by ultrasonic spray pyrolysis. The ZnO homojunction was comprised of N–In codoped p-type ZnO and unintentionally doped n-type ZnO film. Moreover, heterojunction device with n-ZnMgO/ZnO/p-ZnMgO structure was also grown on single-crystal GaAs(1 0 0) substrate by the same method. Ohmic contact layer on n-type ZnO layer and GaAs substrate were formed by Zn/Au and Au/Ge/Ni electrodes, respectively. Distinct light emission was observed under forward current injection at room temperature. The origin of electroluminescence emission was supposed to be attributed to a radiative recombination through deep-level defects in the structure.