Material and electrical properties of N-polar (GaN)/InN surfaces

Angle-resolved XPS-analysis of the bare InN surface has revealed surface electron accumulation and negative band bending by about 0.65 eV at a distance of 1.1 nm. On the other hand this effect was substantially reduced by capping the InN surface by 2 to 4 monolayer of GaN. Negative polarisation charge at the GaN/InN interface of (partially) strained cap layer together with elimination of dangling bonds at the InN surface were consequently suggested. RIE in CCl2F2 provided highly selective etching of GaN over InN. Al2O3 deposited by ALD on (GaN)/InN surface created structures with metal-insulator-metal-like behaviour.