Band alignment in CdS-α-Te van der Waals heterostructures for photocatalytic applications: influence of biaxial strain and electric field

• Published in: Physical chemistry chemical physics : PCCP 2024-12, Vol.26 (47), p.29339-2935
• Main Authors: Tejaswini, G, Sudheer, Anjana E, Vallinayagam, M, Posselt, M, Zschornak, M, Maniprakash, S, Murali, D
• Format: Article
• Language: English
• Subjects: Alignment; Banded structure; Conduction bands; Current carriers; Electric fields; Electronic properties; Electrons; Heterostructures; Optical properties; Photocatalysis; Strain analysis
• ISSN: 1463-9076; 1463-9084; 1463-9084
• DOI: 10.1039/d4cp03368j

We present a comprehensive theoretical analysis of the structural and electronic properties of a van der Waals heterostructure composed of CdS and α-Te single layers (SLs). The investigation includes an in-depth study of fundamental structural, electronic, and optical properties with a focus on their implications for photocatalytic applications. The findings reveal that the α-Te SL significantly influences the electronic properties of the heterostructure. Specifically, the optical properties of the heterostructure are notably dominated by the contribution of α-Te. The layer-resolved density of states analyses indicate that the valence and conduction bands near the Fermi level are mainly determined by the α-Te SL. Band edge analyses demonstrate a type-I band alignment in the heterostructure, causing charge carriers (electrons and holes) to localize within α-Te. The electronic properties can be further modulated by external strain and electric fields. Remarkably, the CdS-α-Te heterostructure undergoes a transition from type-I to type-II band alignment when subjected to biaxial strain and an external electric field. This may be interesting for the application of the heterostructure for photocatalysis. A comprehensive theoretical analysis of the structural and electronic properties of a van der Waals heterostructure composed of CdS and α-Te single layers (SLs).