Comprehensive Polarity Regulation of WSe2 Field‐Effect Transistors Enabled by Combining Contact Engineering and Plasma Doping

Abstract

Two‐dimensional semiconductors are considered as promising candidates in next‐generation nanoelectronics. The polarity regulation, however, has been a great obstacle to their applications. Herein, a strategy to comprehensively modulate the polarity of WSe2 field‐effect transistors (FETs) by combining contact engineering and plasma doping is demonstrated. N‐type and ambipolar WSe2 FETs are obtained by indium (In) and chromium (Cr) contact, respectively. Meanwhile Cr contact and mild oxygen plasma doping are employed simultaneously to realize p‐type WSe2 FET. High on/off ratio of ≈107 has been achieved for both n‐type and p‐type WSe2 FETs. Subsequently, they are connected in series to construct a homogeneous complementary logic inverter and a lateral p–n diode. Anti‐ambipolar transfer characteristics, therefore, are accessed from the inverter. And the forward to backward rectifying ratio reaches 106 for the p–n diode. The proposed strategy paves the way for practical applications of WSe2 FETs in logic circuits and optoelectronics.