Analysis of interface electronic structure in InxGa1−xN/GaN heterostructures

Abstract

Capacitance–voltage profiling was used to measure interfacial polarization charge densities and conduction-band offsets at InxGa1−xN/GaN heterojunction interfaces for x=0.054 and 0.09. A variant of the conventional analysis technique used to deduce interface charge density and band-offset values from capacitance–voltage data was developed and applied. Conduction-band offsets of 0.09±0.07 and 0.22±0.05 eV are obtained for x=0.054 and 0.09, respectively. Polarization charge densities derived from these measurements are (1.80±0.32)×1012 and (4.38±0.36)×1012 e/cm2 for x=0.054 and 0.09, respectively. These values are somewhat lower than those predicted theoretically, but are in good agreement with values inferred from a substantial body of optical data reported for InxGa1−xN/GaN quantum-well structures.