TY - JOUR
T1 - Quasi-Van der Waals Epitaxial Growth of γ′-GaSe Nanometer-Thick Films on GaAs(111)B Substrates
AU - Yu, Mingyu
AU - Iddawela, Sahani Amaya
AU - Wang, Jiayang
AU - Hilse, Maria
AU - Thompson, Jessica L.
AU - Reifsnyder Hickey, Danielle
AU - Sinnott, Susan B.
AU - Law, Stephanie
N1 - Publisher Copyright:
© 2024 American Chemical Society
PY - 2024/7/2
Y1 - 2024/7/2
N2 - 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.
AB - 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.
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U2 - 10.1021/acsnano.4c04194
DO - 10.1021/acsnano.4c04194
M3 - Article
C2 - 38870462
AN - SCOPUS:85196503778
SN - 1936-0851
VL - 18
SP - 17185
EP - 17196
JO - ACS nano
JF - ACS nano
IS - 26
ER -