A nanoscale non-contact electrical measurement has been developed based on Auger electron spectroscopy. This approach used the speciality of Auger electron, which is self-generated and free from external influences, to overcome the technical limitati
ons of conventional measurements. The detections of the intrinsic local charge and internal electric field for nanostructured materials were achieved with resolution below 10 nm. As an example, the electrical properties at the GaN/AlGaN/GaN nanointerfaces were characterized. The concentration of the intrinsic polarization sheet charges embedded in GaN/AlGaN nanointerfacial layers were accurately detected to be -4.4 e/nm^2. The mapping of internal electric field across the nanointerface revealed the actual energy band configuration at the early stage of the formation of two-dimensional electron gas.
We present first-principles calculations of AlGaN/GaN superlattice, clarifying the microscopic origin of the light emission and revealing the effect of local polarization within the quantum well. Profile of energy band and distributions of electrons
and holes demonstrate the existence of a main active site in the well responsible for the main band-edge light emission. This site appears at the position where the local polarization becomes zero. With charge injection, the calculated optical spectra show that the broadening of the band gap at the active site leads to the blueshift of emission wavelength.
