Tailorable Rectification: A study of Vertical Transport in AlGaN/GaN Heterostructures

In this paper, we report calculations that show that a metal-polar semiconductor heterostructure can exhibit highly controllable non-linear current-voltage (I-V) characteristics. Change in barrier thickness can alter the characteristics from Schottky-like to ohmic in different bias regimes. The origin of these unusual effects is a large electric field (> 106 V/cm) and high sheet charge (∼1013 – 1014 cm-2) without doping, in the polar heterostructure. Theoretical calculation of the tunneling current density in these systems indicates that very interesting non-linear behaviour is shown by theseystems, ev en in the undoped case. Choice of suitable compositions of the materials and thicknesses can be used to tailor devices with desired characteristics.