Physical properties of novel Tin-chalcogenides heterostructures: A first-principles study

Bakhtiar Ul Haq, Salem AlFaify, R. Ahmed, Faheem K. Butt, Muhammad Tahir, Sajid Ur Rehman, M. M. Alsardia, Se Hun Kim

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

In recent years, the van der Waals (vdW) Heterostructures (HTSs) are broadly studied for their capabilities to modulate the performance of two-dimensional (2D) materials. Herein, we constructed four types of vdW HTSs by vertically stacking the α-polytype and δ-polytype of single-layered SnS and SnSe. The constructed HTSs have been designated as HTS-I (SnS(α)/SnS(δ)), HTS-II (SnSe(α)/SnSe(δ)), HTS-III (SnS(α)/SnSe(δ)), and HTS-IV (SnSe(α)/SnS(δ)) and their physical properties are systematically explored by the first-principles approach. The electron density mapping revealed that the monolayers constituting these HTSs are stacked by vdW coupling which persists for interlayer distance (Δy) up to ∼7 Å. However, these tin-chalcogenide-based HTSs demonstrated the highest formation energies (Ef) and binding energies (Eb) for Δy = ∼3.75 Å. The electronic structure calculations revealed them as semiconductors of indirect bandgaps of magnitude 1.22, 1.28, 1.06, and 1.22 eV recorded for HTS-I, HTS-II, HTS-III, and HTS-IV, respectively. They exhibited type-II (staggered) band alignment where the valence band maximum occurs in the δ-type of monolayer and the conduction band minimum is located in α-type of monolayers that causes the splitting of the photo-generated electron-hole pairs at the interface. Therefore, the staggering gap and large density of states observed near the bandgap edges have triggered a significantly improved optical absorption in these HTSs compared to freestanding monolayers. Moreover, the transparent nature of these HTSs has been recognized against incident light of energy less than 5 eV. These predictions illustrate the development of vdW HTSs as an effective approach to improve the functionalities of 2D materials for advanced technological applications.

Original languageEnglish
Article number106820
JournalMaterials Science in Semiconductor Processing
Volume149
DOIs
Publication statusPublished - Oct 2022

Keywords

  • Electronic structure calculations
  • Optical properties
  • Tin-chalcogenides
  • Two-dimensional materials
  • Van der Waals heterostructures

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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