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

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.

Automated summary

Stacking two-dimensional materials through van der Waals forces offers a new approach for high-performance optoelectronic and renewable energy devices. This study investigates vdW heterostructures consisting of GeC, ZnO, and Al2SO monolayers using first-principles computations. The results show that GeC (ZnO)-Al2SO vdWHs are stable type-II semiconductors with indirect (direct) band gaps, which significantly suppress the recombination of charge carriers and make them promising for light detection and harvesting applications. The computational findings pave the way for the design of vdWHs for future optoelectronic and photovoltaic devices.