Contactless electroreflectance and photoreflectance studies of n- and p-type-doped GaN with Ga and N face -: art. no. 202103

GaN films with Ga or N face and of n- or p-type doping were grown by plasma-assisted molecular-beam epitaxy. The wurtzite GaN exhibits a large polarization, with spontaneous and piezoelectric components. The direction of polarization, and thus polarization-induced electric fields, F-p is determined by the polarity of the sample. Contactless electroreflectance (CER) has already been employed to study the nature of band bending in GaAs samples. In this work, CER is used to study the band bending of the GaN samples. It was found that the phase of CER is determined by the type of doping, rather than by the polarity of the surface. Additionally, the photoreflectance (PR) spectra were also measured. Comparing CER with PR determines the type of doping. (C) 2005 American Institute of Physics.