Recently, there have been various attempts to demonstrate the feasibility of transition metal dichalcogenide (TMD) transistors for digital logic circuits. A complementary inverter circuit, which is a basic building block of a logic circuit, was implemented in earlier works by heterogeneously integrating n- and p-channel transistors fabricated on different TMD materials. Subsequently, to simplify the circuit design and fabrication process, complementary inverters were constructed on single-TMD materials using ambipolar transistors. However, continuous transition from the electron-conduction to the hole-conduction state in the ambipolar devices led to the problem of a high leakage current. Here, we report a polarity-controllable TMD transistor that can operate as both an n- and a p-channel transistor with a low leakage current of a few picoamperes. The device polarity can be switched simply by converting the sign of the drain voltage. This is because a metal-like tungsten ditelluride (WTe2) with a low carrier concentration is used as a drain contact, which subsequently allows selective carrier injection at the palladium/tungsten diselenide (WSe2) junction. In addition, by using the operating principle of the polarity-controllable transistor, we demonstrate a complementary inverter circuit on a single TMD channel material (WSe2), which exhibits a very low static power consumption of a few hundred picowatts. Finally, we confirm the expandability of this polarity-controllable transistor toward more complex logic circuits by presenting the proper operation of a three-stage ring oscillator.
Bibliographical noteFunding Information:
This research was supported by the Basic Science Research Program, Basic Research Lab Program, and Nano-Material Technology Development Program through National Research Foundation of Korea (NRF) grants funded by the Korea government (MSIP) (2018R1A2A2A05020475, 2017R1A4A1015400 and 2016M3A7B4910426), and the Future Semiconductor Device Technology Development Program (10067739) funded by Ministry of Trade, Industry and Energy (MOTIE), and Korea Semiconductor Research Consortium (KSRC).
All Science Journal Classification (ASJC) codes
- Materials Science(all)