Abstract

Recent discovery of a novel hexagonal phase of GeSe (γ-GeSe) has triggered great interests in nanoelectronics applications owing to its electrical conductivity of bulk phase even higher than graphite while its monolayer is a semiconductor. For potential applications, construction of functional two-dimensional (2D) contacts is indispensable. Herein, via first-principles calculations, we propose the design of van der Waals heterostructures (vdWHs) of γ-GeSe contacting respectively with graphene, 2D h-BN and MoS2, as representatives of metallic, insulator, and semiconductor partners. Our work shows that the h-BN or graphene layer donates electrons to the γ-GeSe layer, resulting in n doping in γ-GeSe, while the MoS₂ layer accepts electrons from the γ-GeSe layer leading to p doping of the latter. The γ-GeSe/BN heterostructure has a type-I band alignment with large band offsets, indicating that BN can be used as an effective passivating layer to protect γ-GeSe from its environmental disturbance while maintaining its major electronic and optical characteristics. For γ-GeSe/graphene heterostructure, it is prone to have a very low-Schottky barrier down to tens of meV, easily overcome by thermal excitation, which can be tunable by strain and external electric field. The γ-GeSe/MoS₂ vdWH forms a Z-scheme interface, which is beneficial for carriers splitting and photon utilization. Our work indicates that γ-GeSe can be well passivated by BN, and form intimate contact with graphene for high charge injection efficiency and with MoS₂ for efficient carriers splitting for redox reactions.

Abstract

Recent discovery of a novel hexagonal phase of GeSe (γ-GeSe) has triggered great interests in nanoelectronics applications owing to its electrical conductivity of bulk phase even higher than graphite while its monolayer is a semiconductor. For potential applications, construction of functional two-dimensional (2D) contacts is indispensable. Herein, via first-principles calculations, we propose the design of van der Waals heterostructures (vdWHs) of γ-GeSe contacting respectively with graphene, 2D h-BN and MoS2, as representatives of metallic, insulator, and semiconductor partners. Our work shows that the h-BN or graphene layer donates electrons to the γ-GeSe layer, resulting in n doping in γ-GeSe, while the MoS₂ layer accepts electrons from the γ-GeSe layer leading to p doping of the latter. The γ-GeSe/BN heterostructure has a type-I band alignment with large band offsets, indicating that BN can be used as an effective passivating layer to protect γ-GeSe from its environmental disturbance while maintaining its major electronic and optical characteristics. For γ-GeSe/graphene heterostructure, it is prone to have a very low-Schottky barrier down to tens of meV, easily overcome by thermal excitation, which can be tunable by strain and external electric field. The γ-GeSe/MoS₂ vdWH forms a Z-scheme interface, which is beneficial for carriers splitting and photon utilization. Our work indicates that γ-GeSe can be well passivated by BN, and form intimate contact with graphene for high charge injection efficiency and with MoS₂ for efficient carriers splitting for redox reactions.

Abstract

Recent discovery of a novel hexagonal phase of GeSe (γ-GeSe) has triggered great interests in nanoelectronics applications owing to its electrical conductivity of bulk phase even higher than graphite while its monolayer is a semiconductor. For potential applications, construction of functional two-dimensional (2D) contacts is indispensable. Herein, via first-principles calculations, we propose the design of van der Waals heterostructures (vdWHs) of γ-GeSe contacting respectively with graphene, 2D h-BN and MoS2, as representatives of metallic, insulator, and semiconductor partners. Our work shows that the h-BN or graphene layer donates electrons to the γ-GeSe layer, resulting in n doping in γ-GeSe, while the MoS₂ layer accepts electrons from the γ-GeSe layer leading to p doping of the latter. The γ-GeSe/BN heterostructure has a type-I band alignment with large band offsets, indicating that BN can be used as an effective passivating layer to protect γ-GeSe from its environmental disturbance while maintaining its major electronic and optical characteristics. For γ-GeSe/graphene heterostructure, it is prone to have a very low-Schottky barrier down to tens of meV, easily overcome by thermal excitation, which can be tunable by strain and external electric field. The γ-GeSe/MoS₂ vdWH forms a Z-scheme interface, which is beneficial for carriers splitting and photon utilization. Our work indicates that γ-GeSe can be well passivated by BN, and form intimate contact with graphene for high charge injection efficiency and with MoS₂ for efficient carriers splitting for redox reactions.

Abstract

Recent discovery of a novel hexagonal phase of GeSe (γ-GeSe) has triggered great interests in nanoelectronics applications owing to its electrical conductivity of bulk phase even higher than graphite while its monolayer is a semiconductor. For potential applications, construction of functional two-dimensional (2D) contacts is indispensable. Herein, via first-principles calculations, we propose the design of van der Waals heterostructures (vdWHs) of γ-GeSe contacting respectively with graphene, 2D h-BN and MoS2, as representatives of metallic, insulator, and semiconductor partners. Our work shows that the h-BN or graphene layer donates electrons to the γ-GeSe layer, resulting in n doping in γ-GeSe, while the MoS₂ layer accepts electrons from the γ-GeSe layer leading to p doping of the latter. The γ-GeSe/BN heterostructure has a type-I band alignment with large band offsets, indicating that BN can be used as an effective passivating layer to protect γ-GeSe from its environmental disturbance while maintaining its major electronic and optical characteristics. For γ-GeSe/graphene heterostructure, it is prone to have a very low-Schottky barrier down to tens of meV, easily overcome by thermal excitation, which can be tunable by strain and external electric field. The γ-GeSe/MoS₂ vdWH forms a Z-scheme interface, which is beneficial for carriers splitting and photon utilization. Our work indicates that γ-GeSe can be well passivated by BN, and form intimate contact with graphene for high charge injection efficiency and with MoS₂ for efficient carriers splitting for redox reactions.