Quasi-Van der Waals Epitaxial Growth of γ′-GaSe Nanometer-Thick Films on GaAs(111)B Substrates

Mingyu Yu, Sahani Amaya Iddawela, Jiayang Wang, Maria Hilse, Jessica L. Thompson, Danielle Reifsnyder Hickey, Susan B. Sinnott, Stephanie Law

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

GaSe is an important member of the post-transition-metal chalcogenide family and is an emerging two-dimensional (2D) semiconductor material. Because it is a van der Waals material, it can be fabricated into atomic-scale ultrathin films, making it suitable for the preparation of compact, heterostructure devices. In addition, GaSe possesses unusual optical and electronic properties, such as a shift from an indirect-bandgap single-layer film to a direct-bandgap bulk material, rare intrinsic p-type conduction, and nonlinear optical behaviors. These properties make GaSe an appealing candidate for the fabrication of field-effect transistors, photodetectors, and photovoltaics. However, the wafer-scale production of pure GaSe single-crystal thin films remains challenging. This study develops an approach for the direct growth of nanometer-thick GaSe films on GaAs substrates by using molecular beam epitaxy. It yields smooth thin GaSe films with a rare γ′-polymorph. We analyze the formation mechanism of γ′-GaSe using density-functional theory and speculate that it is stabilized by Ga vacancies since the formation enthalpy of γ′-GaSe tends to become lower than that of other polymorphs when the Ga vacancy concentration increases. Finally, we investigate the growth conditions of GaSe, providing valuable insights for exploring 2D/three-dimensional (3D) quasi-van der Waals epitaxial growth.

Original languageEnglish (US)
Pages (from-to)17185-17196
Number of pages12
JournalACS nano
Volume18
Issue number26
DOIs
StatePublished - Jul 2 2024

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • General Engineering
  • General Physics and Astronomy

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