Selective Defect Engineering for Gate-Controlled yet Contact-Transparent Bi2O2Se Transistors
Journal
ACS Nano
Journal Volume
20
Journal Issue
25
Start Page
18315
End Page
18323
ISSN
1936-0851
1936-086X
Date Issued
2026-05-26
Author(s)
Nguyen, Huynh-Uyen-Phuong
Lee, Tai-Ting
Hsu, Hung-Chang
Shih, Chih-Yuan
Cheng, Chi-Chun
Tran, Luc-Phuong-Nhu
Chien, Hsin-Chien
Fei, Wen-Yuan
Woon, Wei-Yen
Lin, Yung-Chang
Suenaga, Kazu
Lin, Yen-Fu
Chou, Mei-Yin
Chiu, Po-Wen
Abstract
Two-dimensional semiconductors offer a pathway toward ultrascaled electronics, yet achieving strong electrostatic gate control without sacrificing low-resistance contacts remains a fundamental challenge. Here, we report a selective defect-engineering strategy that addresses this gate-contact trade-off in Bi2O2Se transistors. Low-temperature nitrogen incorporation passivates selenium vacancies through robust N–Bi bonding, suppressing intrinsic self-doping while preserving the intrinsic band dispersion without introducing midgap states. Density functional theory and scanning tunnelling spectroscopy reveal that nitrogen provides acceptor-like compensation by neutralizing vacancy-induced donor states, rather than through conventional substitutional doping. As a result, the Fermi level shifts toward midgap, enabling precise carrier-density modulation while maintaining band-like transport. By spatially confining nitrogen incorporation to the channel region, Bi2O2Se field-effect transistors are converted from depletion to enhancement mode, achieving high electron mobility and on/off ratios up to 109 while preserving ohmic, contact-transparent injection. This selective defect-engineering approach decouples channel electrostatics from contact properties and provides a potentially scalable, thermally benign route toward gate-controllable, contact-transparent two-dimensional transistors compatible with integrated logic architectures.
Subjects
Bi2O2Se transistors
contact-transparent
gate-contact trade-off
nitrogen-incorporation
self-doping suppression
Publisher
American Chemical Society (ACS)
Type
journal article