Comparison of ion-beam-assisted molecular beam epitaxy with conventional molecular beam epitaxy of thin hexagonal gallium nitride films

Abstract

Structural and electronic properties of hexagonal gallium nitride thin films on 6H–SiC, prepared by both low-energy ion-beam-assisted growth as well as molecular beam epitaxy (MBE), have been compared. According to X-ray diffraction and transmission electron microscopy, films deposited by ion-beam-assisted growth contain a significantly lower defect density than MBE films. Moreover, infrared reflectance spectroscopy and photoluminescence measurements substantiate the improvement of the electrical and optical parameters, respectively, if an ion assists the growth of the film. The advanced structural, optical and electrical properties are discussed in the context of enhanced surface mobility during growth, provoked by ion-beam irradiation, resulting in a reduced lattice defect formation probability.