Ab-initio study of Schottky barrier heights at metal-diamond specialIntscript interfaces

Diamond electronic devices have attracted great attention in the field of high power and high frequency ap-plications due to their excellent properties. For diamond electronics, metal and diamond contacts are important for the electronic device performance, with Schottky barrier heights (SBHs) playing a crucial role in the trans-mission properties of diamond devices. To make sense of their electrical characteristics, the interface supercells of diamond (1 1 1) with diverse metals have been explored using first-principles calculations. Clear metal-induced gap states (MIGS) can be observed at the interface, resulting in an enhanced Fermi-level pinning effect, with a pinning factor of 0.3. The results surprisingly show that there is a larger transverse tunneling probability and a smaller longitudinal tunneling probability for all diamond contact interfaces. All interfaces studied are p-type contacts with the metal Fermi level close to the diamond valance band edge. The low work function metals such as Sc and Ti are excellent at generating Schottky contacts with relatively higher SBHs (-1.0 eV +/- 0.6 eV). Pt and Ni have a smallest barrier height of -0.5 eV, making them ideal for ohmic electrodes with low contact resis-tance. The calculated SBHs are within the range of the experimental findings. This work gives insight into the electrical structural changes at the contact interface between metal and diamond, which provides a theoretical basis for selecting suitable electrodes for high-power diamond devices.

Automated summary

Diamond electronic devices have gained attention for high power and high frequency applications. The interface between metal and diamond is crucial for device performance, with Schottky barrier heights (SBHs) playing a significant role. This study investigates metal-induced gap states (MIGS) at the diamond (111) interface using first-principles calculations. The results show larger transverse tunneling probability and smaller longitudinal tunneling probability for all diamond contact interfaces. Low work function metals such as Sc and Ti generate higher SBHs (-1.0 eV +/- 0.6 eV), while Pt and Ni have a smaller barrier height of -0.5 eV, making them suitable for low contact resistance ohmic electrodes. The calculated SBHs are consistent with experimental findings. This work provides insights into the electrical structural changes at the metal-diamond contact interface and aids in selecting suitable electrodes for high-power diamond devices.