Growth of c-axis oriented GaN films on quartz by pulsed laser deposition

摘要

We have successfully fabricated highly oriented GaN films on ZnO-buffered quartz by Nd:YAG pulsed laser deposition to develop large area and low cost optoelectronic devices. The quality of the films was investigated as functions of deposition temperature and ambient pressure by means of X-ray diffraction, scanning electron microscopy, infrared reflectance and optical transmission spectroscopy. It was found that c-axis oriented GaN films could be grown on ZnO-buffered quartz substrates at temperatures from 300 to 800 ℃ and inactivated N_2 flow from 10~(-3) to 2.0 Torr. The crystallinity, surface morphology and optical transmittance of the films could be improved with increasing deposition temperature and were optimized at 800 ℃. A reststrahlen band was observed at 568 cm~(-1), confirming that GaN was indeed overlaid on ZnO-buffered quartz. The present GaN/ZnO bilayer structure has showed optical transmittance of about 60%.