Optoelectronic and photocatalytic behaviour of a type-II GaAlS 2 /HfS 2 heterostructure: ab initio study

• Published in: Nanotechnology Vol. 35; no. 31; p. 315703
• Main Authors: Mehta, Disha, Naik, Yashasvi, Modi, Nidhi, Parmar, P R, Thakor, P B
• Format: Journal Article
• Language: English
• Published: England 29.07.2024
• Subjects: optoelectronic behaviour; GaAlS2/HfS2 heterostructure; Z-scheme; strain effect; photocatalytic activity; type-II band alignment
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/1361-6528/ad43f3

Theoretical examination based on first principle computation has been conducted for van der Waals heterostructure (vdwHS) GaAlS /HfS including structural, optoelectronic and photocatalytic characteristics. From the adhesion energy calculation, the AB configuration of GaAlS /HfS vdwHS is the most stable. A type-II GaAlS /HfS vdwHS is a dynamically and thermally stable structure. The band edge position, projected band, and projected charge densities verify the type-II alignment of GaAlS /HfS vdwHS. For GaAlS /HfS , GaAlS is acting as a donor and HfS is acting as an acceptor ensured by the charge density difference plot. The electron localized function validates the weak van der Waals interaction between GaAlS and HfS . The GaAlS /HfS vdwHS possess an indirect bandgap of 1.54 eV with notable absorption in the visible range. The findings assure that the GaAlS /HfS vdwHS is an efficient photocatalyst for pH 4-8. The band alignment of GaAlS /HfS is suitable for Z-scheme charge transfer. The strain influenced band edge suggests that the GaAlS /HfS vdwHS remains photocatalytic for strain-4%to+6%in both cases of uniaxial and biaxial strains.