Geometry and bias dependence of trapping effects in planar GaN nanodiodes

Pulsed and transient measurements performed in planar nanodiodes fabricated on an AlGaN/GaN heterolayer reveal the influence of surface and bulk traps on the I-V characteristic and AC impedance. Rectangular and V-shape diodes of different lengths and widths have been measured. Surface trapping effects become relevant in narrow channels, as the surface to volume ratio of the device is increased, while in wider rectangular and V-shape diodes bulk trapping effects prevail.