
304 Gallium Nitride (GaN): Physics, Devices, and Technology
probability reduces due to the increased thickness of the barrier. With t >t
cr
, degen-
erate carrier gases accumulate at the GaN/InGaN interface reducing the electric eld
in the InGaN layer if the InGaN layer thickness is further increased. Equilibrium
band diagrams of the GaN/InGaN/GaN structure with increasing thicknesses of
InGaN layer are shown in Figure 9.3.
Under reverse bias, the electrons in the valence band of p-GaN tunnel across the
p-depletion region (intra-valence band), InGaN (interband), and n-depletion region
(intra-conduction band), entering the conduction band of n-Ga ...