It is demonstrated that the electric dipole layer due to the overlapping of electron wavefunctions at metal/graphene contact results in negative Fermi-level pinning effect on the region of GaAs surface with low interface-trap density in metal/graphene/n-GaAs(001) junction. The graphene interlayer takes a role of diffusion barrier preventing the atomic intermixing at interface and preserving the low interface-trap density region. The negative Fermi-level pinning effect is supported by the Schottky barrier decreasing as metal work-function increasing. Our work shows that the graphene interlayer can invert the effective work-function of metal between high and low, making it possible to form both Schottky and Ohmic-like contacts with identical (particularly high work-function) metal electrodes on a semiconductor substrate possessing low surface-state density.
@article{arxiv.1907.06165,
title = {Negative Fermi-level Pinning Effect of Metal/n-GaAs(001) Junction with Graphene Interlayer},
author = {Hoon Hahn Yoon and Wonho Song and Sungchul Jung and Junhyung Kim and Kyuhyung Mo and Gahyun Choi and Hu Young Jeong and Jong Hoon Lee and Kibog Park},
journal= {arXiv preprint arXiv:1907.06165},
year = {2022}
}