Rapid Delineation of Extended Defects in GaN and a Novel Method for their Reduction

Availability of reliable and quick methods to investigate extended defects and polarity in GaN films are of great interest to researchers investigating and exploiting GaN-based structures. The step immediately following the determination of defect density (DD) is to explore ways in which the DD can be reduced. In this paper, we report a systematic investigation of DD determination in GaN which is followed by a novel technique, use of quantum dots, to reduce the DD. We have used photo-electrochemical (PEC) and hot wet etching to determine the DD. We found the density of whiskers formed by the PEC process to be similar to the density of hexagonal pits formed by wet etching and to the dislocation density obtained by transmission electron microscopy (TEM). Hot wet etching was also used to investigate the polarity of MBE-grown GaN films together with convergent beam electron diffraction (CBED) and atomic force microscopy (AFM).