Heterostructure WSe₂−Ga₂O₃ Junction Field-Effect Transistor for Low-Dimensional High-Power Electronics

Abstract

Layered materials separated from each bulk crystal can be assembled to form a strain-free heterostructure by using the van der Waals interaction. We demonstrated a heterostructure n-channel depletion-mode β-GaO junction field-effect transistor (JFET) through van der Waals bonding with an exfoliated p-WSe flake. Typical diode characteristics with a high rectifying ratio of ∼10 were observed in a p-WSe/n-GaO heterostructure diode, where WSe and β-GaO were obtained by mechanically exfoliating each crystal. Layered JFETs exhibited an excellent I- V output as well as I- V transfer characteristics with a high on/off ratio (∼10) and low subthreshold swing (133 mV/dec). Saturated output currents were observed with a threshold voltage of -5.1 V and a three-terminal breakdown voltage of +144 V. Electrical performances of the fabricated heterostructure JFET were maintained at elevated temperatures with outstanding air stability. Our WSe-GaO heterostructure JFET paves the way to the low-dimensional high-power devices, enabling miniaturization of the integrated power electronic systems.

SnSe/MoS2 van der Waals Heterostructure Junction Field‐Effect Transistors with Nearly Ideal Subthreshold Slope

“…[12] Recent studies of 2D materials [13] have revealed a variety of 2D semiconductors (2DSCs) with excellent electronic properties [14][15][16][17] and ultrathin body thickness. However, despite several studies on 2DSCs based JFETs reported to date, [23][24][25][26] the SS achieved in these devices remain > 100 mV dec −1 , far from the ideal value of 60 mV dec −1 . [11] Additionally, the dangling bond free van der Waals (vdW) interface formed by 2DSCs could feature a trapping free interface to promise nearly ideal junction characteristics.…”

“…The maximum channel mobility of a JFET can be calculated by expression [23,24] We also investigated the output characteristics (Figure 2d) of the SnSe/MoS 2 JFET at various top-gate voltage. The maximum channel mobility of a JFET can be calculated by expression [23,24] We also investigated the output characteristics (Figure 2d) of the SnSe/MoS 2 JFET at various top-gate voltage.…”

“…[11] Additionally, the dangling bond free van der Waals (vdW) interface formed by 2DSCs could feature a trapping free interface to promise nearly ideal junction characteristics. However, despite several studies on 2DSCs based JFETs reported to date, [23][24][25][26] the SS achieved in these devices remain > 100 mV dec −1 , far from the ideal value of 60 mV dec −1 . Here, we present an n-channel JFET based on a SnSe/MoS 2 heterostructure with vdW interface between multiple layer p-type SnSe gate and ultrathin n-type MoS 2 channel.…”

“…Similar with conventional MOSFET, the field-effect mobility, as one of the most important parameter, can be readily estimated from transfer characteristics of JFET. The maximum channel mobility of a JFET can be calculated by expression [23,24] LG V WHI µ = by considering similar MoS 2 thickness in two devices. The transconductance extracted from Figure 2b is shown in Figure 2c, where the maxium transconducance of 26.9 µS is reached at V DS = 2 V. By obtaining the Hall voltage V H of 2.54 mV from few-layer MoS 2 Hall bar device ( Figure S4, Supporting Information) at 5 T magnetic field and 2.5 µA current, the effective field-effect mobility of 27.3 cm 2 V −1 s is estimated, which is similar with typical MoS 2 MOSFET.…”

“…These SS numbers are much lower than that in reported 2DSCs based JFETs reported prevously. [23][24][25][26] To show the device-to-device deviation, we also plot the SS of five devices as function of I DS in Figure 2f. The devices show close to limit SS, but curves from device 5 to 1 are exhibiting more noisy data and smaller low-SS current range, i.e., worse subthreshold performance.…”