Unveiling Versatile Electronic Properties and Contact Features of Metal-Semiconductor Graphene/γ-Ge 2 SSe van der Waals Heterostructures.

Recently, searching for a metal-semiconductor junction (MSJ) that exhibits low-contact resistance has received tremendous consideration, as they are essential components in next-generation field-effect transistors. In this work, we design a MSJ by integrating two-dimensional (2D) graphene as the metallic electrode and 2D Janus γ-Ge 2 SSe as the semiconducting channel using first-principles simulations. All the graphene/γ-Ge 2 SSe MSJs are predicted to be energetically, mechanically, and thermodynamically stable, characterized by the weak van der Waals (vdW) interactions. The graphene/γ-SGe 2 Se MSJ-vdWH form the n -type Schottky contact (SC), while the graphene/γ-SeGe 2 S MSJ-vdWH form the p -type one, suggesting that the switching between p -type and n -type SC in the graphene/γ-Ge 2 SSe MSJ-vdWHs can occur spontaneously by simply altering the stacking patterns, without requiring any external conditions. Notably, the contact features, including contact types and barriers of the graphene/γ-Ge 2 SSe MSJs are significant in versatility and can be altered by applying electric gating and adjusting interlayer spacing. Both the applied electric gating and strain engineering induce switchability between p - and n -type and SC to OC in the graphene/γ-Ge 2 SSE MSJs. This versatility underscores the potential of the graphene/γ-Ge 2 SSe MSJ for next-generation applications that require low-contact resistance and high performance.