Abstract:The applications of ZnO∶Al substitute ITO for transparent conductive layer in GaN based LED were researched. AZO films were prepared by pulsed laser deposition and magnetron sputtering. Then the physical mechanism of poor ohmic contacts between AZO and p type GaN layer was analyzed, and the contact resistance was improved by inserting ITO layer simultaneously. For the experiments, ITO 20nm/AZO 500nm composite transparent conductive layer was prepared successfully, and the GaN based green LED was obtained with the brightness of 380.88mcd, wavelength of 525.74nm and voltage of 3.35V. The result is equivalent to the performance of a single ITO transparent conductive layer, and it reduces the usage of ITO and the process cost.