Nitridation effect of the α-Al2O3 substrates on the quality of the GaN films grown by pulsed laser deposition
GaN films have been grown on the nitrided and non-nitrided α-Al2O3 substrates by pulsed laser deposition (PLD). The surface morphologies and structural properties of these as-grown GaN films have been investigated carefully. This reveals that, when the nitridation process is performed on the α-Al2O3 substrates, the surface morphologies and structural properties of the as-grown GaN films grown on the as-nitrided α-Al2O3 substrates are improved dramatically. The effect of nitridation on the properties of GaN films and the growth mechanism of GaN films on nitrided α-Al2O3 substrates by PLD have been carefully studied. An effective approach to achieve high-quality GaN films on α-Al2O3 substrates by PLD is hence presented.