Optical investigation of band-edge structure and built-in electric field of AlGaN/GaN heterostructures by means of thermoreflectance, photoluminescence, and contactless electroreflectance spectroscopy

Optical investigation of band-edge structure and built-in electric field of AlGaN/GaN heterostructures by means of thermoreflectance, photoluminescence, and contactless electroreflectance spectroscopy