Characterization of thin layers of n- and p-type GaN

Technological improvement of GaN-based devices for electronic and optoelectronic applications makes essential both monitoring and controlling point and extended defects, which can have detrimental effects in device performance. For gallium nitride, thickness is a key parameter controlling the density and distribution of defects, especially extended ones. In this work highly defective thin GaN layers, both p- and n-type, have been characterized by photocurrent (PC) and time-resolved cathodoluminescence (TRCL) spectroscopy in order to evidence the presence of defect-related bands influencing the electrical and optical activity of the material. Scanning microscopy-based techniques, namely electron beam induced current (EBIC), CL imaging and optical beam induced current (OBIC) have been applied to investigate the recombination activity and the spatial distribution of the extended defects.