# Semi-analytical model of the contact resistance in two-dimensional semiconductors

**Authors:** Roberto Grassi, Yanqing Wu, Steven J. Koester, Tony Low  
**arXiv:** [1701.07758](https://arxiv.org/abs/1701.07758)  
**Date:** 2017-01-26  
**Summary page:** https://www.summarizepaper.com/en/paper/1701.07758v1/

## Key points

- Contact resistance in electronic devices based on 2D semiconductors is a significant performance bottleneck
- These semiconductors have Schottky contacts instead of Ohmic contacts
- Existing models oversimplify the transport problem by neglecting the 2D transport nature and modulation of the Schottky barrier height
- A semi-analytical model based on Bardeen's transfer Hamiltonian approach was developed to address this issue
- The model successfully reproduces experimental observations of metallic behavior in contact resistance
- Contact resistance exhibits a decreasing trend with decreasing temperature at high gate voltage
- Unique electronic properties in 2D semiconductors can be harnessed for improved device performance
- The study provides valuable insights into understanding and optimizing contact resistance in electronic devices based on 2D semiconductors
- The developed semi-analytical model offers a more accurate description of the transport problem and can guide future research efforts.

## Summary

The contact resistance in electronic devices based on two-dimensional layered (2D) semiconductors is a significant performance bottleneck. Unlike traditional devices, these semiconductors have Schottky contacts instead of Ohmic contacts. While it is widely accepted that the injection mechanism changes from thermionic to tunneling with gate biasing, existing models oversimplify the transport problem by neglecting the 2D transport nature and the modulation of the Schottky barrier height, especially in back-gated devices. To address this issue, a team of researchers led by Roberto Grassi developed a semi-analytical model based on Bardeen's transfer Hamiltonian approach. This model takes into account both the 2D transport nature and the modulation of the Schottky barrier height. Surprisingly, their model successfully reproduces several experimental observations of a metallic behavior in the contact resistance. One key finding is that the contact resistance exhibits a decreasing trend with decreasing temperature at high gate voltage. This observation suggests that there are unique electronic properties at play in these 2D semiconductors which can be harnessed for improved device performance. Overall, this study provides valuable insights into understanding and optimizing contact resistance in electronic devices based on 2D semiconductors. The developed semi-analytical model offers a more accurate description of the transport problem and can guide future research efforts towards overcoming this performance bottleneck.