Facet-Dependent Electrical Conductivity Properties of GaN Wafers

An intrinsic {0001} GaN wafer cut to expose the {100}/{100} side faces allows examination of its conductivity properties with respect to the crystal faces. Interestingly, the {100} face shows a 10-fold higher photoluminescence peak intensity than the {0001} face. The {0001} face is 60-fold more conductive at 6 V than the {100} face, demonstrating the presence of an electrical facet effect. The conductivity difference can be rationalized assuming different degrees of band bending at these crystal surfaces. Asymmetric I–V curves were obtained with electrical connections made to both faces simultaneously, showing the potential of using this behavior to fabricate transistors.