Improved Hysteresis and Reliability of MoS 2 Transistors With High-Quality CVD Growth and Al 2 O 3 Encapsulation

We report considerable improvement in the hysteresis and reliability of single-layer MoS2field-effect transistors (FETs) achieved by chemical vapor deposition (CVD) of MoS2and dielectric encapsulation. Our results show that a high-quality 15-nm thick Al2O3layer allows for an efficient protection of the devices from adsorbent-type trapping sites. Combined use of the CVD-grown MoS2as a channel and encapsulation simultaneously leads to at least an order of magnitude smaller hysteresis and up to two orders of magnitude lower long-term drifts of the transistor characteristics. Together with high on/off current ratios (~109) achieved in our devices, this presents a considerable advance in the technology of MoS2FETs. As such, we conclude that both CVD growth of MoS2and encapsulation present important technological steps toward reaching commercial quality standards of next-generation two-dimensional (2D) material technologies.