Enhanced efficiency of Schottky-barrier solar cell with periodically nonhomogeneous indium gallium nitride layer

A two-dimensional finite-element model was developed to simulate the optoelectronic performance of a Schottky-barrier solar cell. The heart of this solar cell is a junction between a metal and a layer of n-doped indium gallium nitride (InξGa₁-ξN) alloy sandwiched between a reflection-reducing front window and a periodically corrugated metallic back reflector. The bandgap of the InξGa₁-ξN layer was varied periodically in the thickness direction by varying the parameter ξ ∈ 0;1. First, the frequency-domain Maxwell postulates were solved to determine the spatial profile of photon absorption and, thus, the generation of electron-hole pairs. The AM1.5G solar spectrum was taken to represent the incident solar flux. Next, the drift-diffusion equations were solved for the steady-state electron and hole densities. Numerical results indicate that a corrugated back reflector of a period of 600 nm is optimal for photon absorption when the InξGa1-ξN layer is homogeneous. The efficiency of a solar cell with a periodically nonhomogeneous InξGa₁-ξN layer may be higher by as much as 26.8% compared to the analogous solar cell with a homogeneous InξGa₁-ξN layer.