Gallium nitride films made by liquid target pulsed laser deposition

In this paper, formation of single c-axis oriented wurtzite gallium nitride films on various substrates as fused silica, Si and sapphire with ZnO buffer layers by liquid target pulsed laser deposition is reported. The deposition conditions were optimized with a temperature of 600 degrees C and an ammonia pressure of 750mTorr. X-ray diffraction, scanning electron microscopy, tunneling electron microscopy, room temperature Hall effect measurement, UV/VIS spectrometry, Rutherford backscattering spectroscopy and x- ray photoelectron spectroscopy were used to characterize the as-grown films. It is shown that high quality single c-axis orientation stoichiometric gallium nitride films could be formed with a thin zinc oxide buffer layer. The FWHM of x- ray rocking curve of the peak of GaN grown on ZnO/sapphire was as narrow as 0.52 degrees. It was also found that the surface morphology was greatly improved with the zinc oxide buffer.