Photolithography-Induced Doping and Interface Modulation for High-Performance Monolayer WSe2 P-Type Transistors
Journal
Nano Letters
Series/Report No.
Nano Letters
Journal Volume
25
Journal Issue
9
Start Page
3571
End Page
3578
ISSN
1530-6984
1530-6992
Date Issued
2025-02-21
Author(s)
Yu-Tung Lin
Yu-Wei Hsu
Zih-Yun Fong
Ming-Yu Shen
Ching-Hao Hsu
Shu-Jui Chang
Ying-Zhan Chiu
Shao-Heng Chen
Nien-En Chiang
I-Chih Ni
Tsung-En Lee
DOI
10.1021/acs.nanolett.4c06407
Abstract
To mitigate Fermi-level pinning (FLP) at the contact of two-dimensional (2D) transition metal dichalcogenides and enhance their hole carrier concentration, a 1.8 nm-thick p-doping layer is formed via photolithography. This surface treatment significantly reduces the contact resistance (RC) to ∼4.8 kΩ·um in monolayer (1L) WSe2 p-type field-effect transistors (p-FETs) and increases hole carrier concentration by 1.4 times, resulting in a field-effect mobility of ∼75 cm/V·s. After subsequent helium ion-beam lithography, the Fermi level can still be modulated from 4.25 to 4.55 eV due to the ultrathin buffer layer. This approach enables high-performance p-FETs with 1L-WSe2 channels, achieving a maximum on-state current density of 420 μA/μm at a VD of -1 V and ultralow RC of ∼0.8 kΩ·um by the combination of the MoOx encapsulation for additional p-doping. These results demonstrate that 1L-WSe2 p-FETs can attain performance comparable to 2D n-FETs, paving the way for high-performance complementary metal-oxide semiconductor transistors with 2D channels.
Publisher
American Chemical Society (ACS)
Type
journal article