Polarity control in a single transition metal dichalcogenide (TMD) transistor for homogeneous complementary logic circuits

• Published in: Nanoscale Vol. 11; no. 27; pp. 12871 - 12877
• Main Authors: Shim, Jaewoo, Jang, Sung woon, Lim, Ji-Hye, Kim, Hyeongjun, Kang, Dong-Ho, Kim, Kwan-Ho, Seo, Seunghwan, Heo, Keun, Shin, Changhwan, Yu, Hyun-Yong, Lee, Sungjoo, Ko, Dae-Hong, Park, Jin-Hong
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 21.07.2019
• Subjects: Carrier density; Carrier injection; Chalcogenides; Circuit design; Construction materials; Inverters; Leakage current; Logic circuits; Palladium; Polarity; Power consumption; Selenides; Semiconductor devices; Stability; Transistors; Transition metal compounds; Tungsten compounds
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c9nr03441b

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 (WTe 2 ) with a low carrier concentration is used as a drain contact, which subsequently allows selective carrier injection at the palladium/tungsten diselenide (WSe 2 ) 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 (WSe 2 ), 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. We report a polarity controllable TMD transistor that can operate as both an n- and a p-channel transistor. We then demonstrate a complementary inverter circuit on a single TMD material and its expandability toward a three-stage ring oscillator.