Comprehensive polarity regulation of WSe${}_2$ field-effect transistors enabled by combining contact engineering and plasma doping

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 WSe${}_2$ field-effect transistors (FETs) by combining contact engineering and plasma doping is demonstrated. N-type and ambipolar WSe${}_2$ 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 WSe${}_2$ FET. High on/off ratio of ≈10${}^7$ has been achieved for both n-type and p-type WSe${}_2$ 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 10${}^6$ for the p-n diode. The proposed strategy paves the way for practical applications of WSe${}_2$ FETs in logic circuits and optoelectronics. (© 2023 Wiley‐VCH GmbH)