High Schottky barrier heights at metal–semiconductor junctions due to Fermi-level pinning can degrade the performance of electronic devices and increase their energy consumption. Van der Waals contacts between metals and two-dimensional semiconductors without Fermi-level pinning are theoretically possible, but have not been achieved due to the presence of interactions such as interface defects and orbital overlap. Here we show that interaction- and defect-free van der Waals contacts can be formed between a range of metals and two-dimensional semiconductors via a metal deposition process that uses a selenium buffer layer. Our contacts obey the Schottky–Mott rule and have a Fermi-level pinning of –0.91. A comparison between the van der Waals contacts and typical direct metal contacts reveals differences in interface gap distances, band bending and electrical characteristics. Using gold van der Waals contacts, we fabricate p-type tungsten diselenide field-effect transistors that exhibit stable operation with on/off ratio of 106, mobility of 155 cm2 (V s)–1, contact resistance of 1.25 kΩ μm and Schottky barrier height of 60 meV.
|Number of pages||7|
|Publication status||Published - 2022 Apr|
Bibliographical noteFunding Information:
This work was partially supported by an Industry–Academy joint research programme between Samsung Electronics and Yonsei University. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (grant no. 2017R1A5A1014862; SRC programme, vdWMRC center). This work was supported by the NRF grant funded by the Government of Korea (MSIP) (no. 2021M3H4A1A03052566).
© 2022, The Author(s), under exclusive licence to Springer Nature Limited.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering