Annealing Dependence on Structural and Electrical Characteristic of n-ZnO/p-CuGaO₂ Transparent Heterojunction Diode

In order to fabricate transparent p–n devices, a good p-type transparent material is desired but it is difficult to obtain stable p-type conductivity. In this paper we investigate the effect of annealing temperature and annealing duration on the CuGaO₂ thin film structure and diode electrical characteristic. A transparent p-type thin film CuGaO₂ was successfully fabricated on the glass substrate by using RF sputtering deposition method and was annealed at different temperature and duration ranging from 200 °C to 500 °C and 1 to 4 hours at. CuGaO₂ thin film crystalinity is improved at higher temperature and longer duration which is 500 °C and for 3 hours. The optical band gap of the thin film is approximately 3.3 eV. A transparent heterojuntion is fabricated on a transparent glass substrate with device structure ITO/n-ZnO/p-CuGaO₂/Al and I–V measurement shows the device that annealed for 1 hour at 500 °C show better rectification behavior which is 3.8 V.