Band alignment of AlxGa1–xN/Cu2O heterojunctions in dependence on alloy composition x and its effect on the photovoltaic properties

Abstract

The band alignment of p-Cu2O/n-AlxGa1–xN heterojunction with x up to 0.15 was studied by X-ray photoelectron spectroscopy. The conduction band offset between binary Cu2O and ternary AlxGa1–xN is found to decrease with increasing x. The data suggest that a flatband situation in the conduction band of p-Cu2O/n-AlxGa1–xN heterojunctions can be achieved for x about 0.4, which is an Al-content where n-type doping is still feasible. Thus, n-AlxGa1–xN with x between 0.4 and 0.6 may be a suitable window material for heterojunction solar cells with a p-Cu2O absorber layer. The current-voltage characteristics of the p-Cu2O/n-AlxGa1–xN heterojunctions under illumination confirm the anticipated improvement of the photovoltaic properties with increasing x.

Progress in Sputter Growth of β‐Ga2O3 by Applying Pulsed‐Mode Operation

“…The term “window material” results from the fact that the radiation initially passes through this material virtually without interaction and is absorbed subsequently from the absorber layer. In addition to wide‐band‐gap nitride semiconductors such as GaN (3.4 eV) and (3.4 − 3.75 eV) or oxides such as ZnO (3.3 eV), a material, very well suited for such devices as a window layer, might be gallium sesquioxide, Ga 2 O 3 . This material exhibits five different confirmed phases ( α , β , γ , δ , and ε ).…”