Type-II van der Waals heterostructures of GeC, ZnO and Al2SO monolayers for promising optoelectronic and photocatalytic applications

Abstract

Two-dimensional materials stacked via van der Waals (vdW) forces provide a revolutionary route toward high-performance optoelectronic and renewable energy devices. Here, we report vdW heterostructures (vdWHs) consisting of GeC, ZnO and Al2SO monolayers on first-principles computations. GeC (ZnO)-Al2SO vdWHs are both stable type-II semi-conductors with indirect (direct) band gaps. This significantly suppresses the recombina-tion of photogenerated charge carriers across the interface, making them promising for light detection and harvesting applications. Charge transfer from GeC (Al2SO) layer to Al2SO (ZnO) layer leads to p-doping in GeC (Al2SO) and n-doping in Al2SO (ZnO) of GeC (ZnO)-Al2SO vdWHs. In contrast to pristine monolayers, higher carrier mobility promotes charge transfer to the surface and reduces carrier recombination in GeC (ZnO)-Al2SO vdWHs. Further, the absorption spectra indicate redshift (blueshift) and reveal more solar light is absorbed by GeC (ZnO)-AlS2O vdWHs in the visible (ultraviolet) region. The band edge positions suggest that GeC-Al2SO vdWHs can reduce water into H2 but fails to perform an oxidation reaction at pH = 0. More interestingly, ZnO-Al2SO vdWHs can perform redox reactions, making them prominent for overall water-splitting reactions. Our computational findings provide a path for the design of vdWHs for future optoelectronic and photovoltaic devices.& COPY; 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.