2D MoSe₂ Transistor with Polymer‐Brush/Channel Interface

Abstract

Abstract Toward any practical applications of 2D transition metal dichalcogenide (TMD) transistors, two issues are often met. First, threshold voltage ( V th ) of usual TMD 2D field effect transistors (FETs) is located quite away from 0 V, making the device already on and less practical. Second, a large hysteresis exists during transistor operation. Here, hysteresis‐minimized n‐TMD FETs are fabricated using polymer‐brush/channel interface, to extend the 2D FET study to a sensor application. Gated by piezoelectric P(VDF‐TrFE) touch pad that allows dipole switching and instantaneous voltages of +5 and ‐5 V, n‐MoSe 2 FET operates well in its ON/OFF drain current behavior, due to its properly small V th of −5 V. However, n‐MoS 2 FET with a relatively high V th of more than −8 V cannot be suitably switched off. To minimize the gate hysteresis, ultrathin polystyrene‐brush layer is applied between TMD channel and 50 nm thin Al 2 O 3 dielectric. n‐Channel MoS 2 and MoSe 2 FETs exhibit a minimum voltage hysteresis of 1 and 0.5 V, respectively. It is regarded that V th and hysteresis issues are uneasy to resolve but still possible to circumvent by using proper TMD channel and channel/dielectric interface materials.