Growth of GaN by nitridation of seed/catalyst free electrodeposited Ga-based compound materials on graphene on insulator

The nitridation of the electrochemically deposited Ga-based compound material on graphene on insulator towards the formation of GaN/graphene hybrid structure was studied by varying the nitridation time and temperature. First, the growth of Ga-based compounds which contains GaON and Ga2O3 on multi-layer graphene on SiO2/Si using a mixture of NH4NO3 and Ga(NO3)3 by a simple two terminal electrochemical deposition at room temperature was performed. Then, the conversion of the grown structures to the crystalline GaN structure was carried out by nitridating the grown structures in NH3 gas. The properties of the grown structures were critically influenced by the studied nitridation parameters. The complete transformation to hexagonal GaN was achieved at nitridation temperature of 1100 °C and time of above 60 min due to the observation of significant diffraction peaks which correspond to hexagonal GaN planes. Meanwhile no diffraction peaks of GaON and Ga2O3 structure were observed. Temperature and time are the key parameters in a nitridation process where the ammoniation rate of GaON and deoxidization rate of Ga2O3 to generate gaseous Ga2O, increase with temperature and time. It was speculated that a complete transformation can not be realized without a complete ammoniation of GaON and deoxidization of Ga2O3. The change of morphological structures was also observed due to both reactions. The presented method demonstrates the feasibility to realize GaN/ graphene hybrid structure on insulator which is highly demanded in fabricating optoelectronic and sensing devices.