Designing high-efficiency metal and semimetal contacts to two-dimensional semiconductor γ-GeSe

Forming a low-resistance semiconductor-metal contact is a critical step to achieve a high-performance two-dimensional (2D) semiconductor nanoelectronic device. Motivated by the recent discovery of monolayer gamma-GeSe with exceptional high electrical conductivity reaching 10(5) S/m, we computationally investigate the interface contact properties of gamma-GeSe with four representative classes of metallic systems, including 2D semimetal (graphene), 2D metal (NbS2), 3D semimetal (Bi), and 3D metal (Au) using first-principle density functional theory simulations. We found that these metals exhibit rich contact formation physics with 2D gamma-GeSe, yielding contacts of heterostructures with weak and moderate couplings. Importantly, gamma-GeSe/NbS2 is an Ohmic contact while gamma-GeSe/Bi is an n-type Schottky contact with an ultralow barrier height of 0.07 eV. For gamma-GeSe/graphene contact, the electronic properties can be adjusted via the interlayer distance or via an external electric field. Finally, we show that the contact properties can also be further controlled using layer-number engineering of gamma-GeSe. Our findings provide a useful guideline for designing high-performance 2D nanoelectronics based on 2D gamma-GeSe. Published under an exclusive license by AIP Publishing.

Automated summary

Forming a low-resistance semiconductor-metal contact is crucial for high-performance 2D semiconductor nanoelectronic devices. In this study, the interface contact properties of gamma-GeSe with different metallic systems were computationally investigated. Results showed that these metals exhibited rich contact formation physics with gamma-GeSe, forming heterostructures with weak and moderate couplings. Notably, gamma-GeSe/NbS2 showed an Ohmic contact and gamma-GeSe/Bi showed an n-type Schottky contact with an ultralow barrier height. The electronic properties of gamma-GeSe/graphene contact could be adjusted using interlayer distance or external electric field. Additionally, layer-number engineering of gamma-GeSe allowed further control of contact properties.