Electrode Engineering in MoS₂ MOSFET: Different Semiconductor/Metal Interfaces

Abstract

materials has attracted extensive attention in nanoelectronics devices. [1][2][3] Among the large studies on various 2D semiconductor materials, MoS 2 as a transition metal chalcogenides is a credible candidate for channel materials in the future metal-oxide-semiconductor field-effect transistors (MOSFET) because its unique advantages such as suitable bandgap (1.2-1.9 eV), [4] high field-effect mobility (40 cm 2 V -1 s -1 on average), [5] and large on-off ratio (up to 10 8 ). [6][7][8] In addition, MoS 2 MOSFET with the atomic thickness is itself the structure of silicon on insulating layer, which can eliminate the floating body and improve the subthreshold slope. Therefore, the 2D MoS 2 is widely used to research short-channel MOSFET. [9][10][11] In short-channel MOSFET devices, the power consumption is particularly influenced by high contact resistance (R c ) at the metal/semiconductor interfaces. [12,13] In order to reduce the power consumption and increase transmission current, the Ohmic contact is an important factor for 2D MoS 2 MOSFET because it can significantly lower the additional impedance.Compared to the total resistance, the ideal Ohmic R c is relatively small. Hence, the voltage drop across the ideal Ohmic R c The formation ofOhmic contact between metal electrode and 2D semiconductor channel is considered a key factor for performance improvement of 2D metal-oxide-semiconductor field-effect transistors (MOSFET). However, the Schottky barrier at the metal electrode/2D semiconductor interfaces cannot be lowered effectively due to the pinning effect of Fermi levels, which makes it hard to obtain lower Ohmic contact resistance. Until now, although physical transfer metal electrode or inserted tunneling layer has been reported to get rid of the Fermi-level pinning effect, these different designs of electrode engineering are not systematically compared. To serve better Ohmic contact, three different designs of electrode engineering are employed in 2D MoS 2 MOSFET: evaporating Ag electrode on MoS 2 , transferring MoS 2 to Ag electrode, and inserting ultrathin AlO x tunneling layer. Our experimental results demonstrate that the transferring MoS 2 to Ag electrode in 2D MoS 2 MOSFET can obtain the lowest contact resistance and Schottky barrier of 0.45 Ωcm and 12.8 meV, respectively. On this basis, photodiodes with obvious rectifying behavior are fabricated using schemes of electrode engineering, due to their different Schottky barrier high. The detailed contrastive analysis in our three different designs of electrode engineering can provide valuable guidance to optimize the performance of 2D semiconductor MOSFET.

Microneural Network System Based on MoS2/h-BN/Graphene van der Waals Heterojunction Transistor

“…where C i is the gate oxide capacitance per unit area, L is the channel length, W is the channel width, and g m = dI ds /dV g is the transconductance. 17 Due to the synergistic effect of graphene and h-BN, our MoS 2 /h-BN/graphene vdW heterojunction transistor achieves the highest electron mobility of 340 cm 2 /(V•s) at room temperature. 18 With the temperature decreases (<100 K), the scattering mechanism in the MoS 2 transistor and MoS 2 /graphene transistor gradually shifts from lattice scattering to impurity scattering, leading to a decrease in their mobility.…”

“…Figure f presents the variation of field-effect mobility (μ) with temperature for the MoS 2 transistor, MoS 2 /graphene vdW heterojunction transistor, and MoS 2 /h-BN/graphene vdW heterojunction transistor. The μ is calculated by μ = 1 C normali L W g normalm V ds , where C i is the gate oxide capacitance per unit area, L is the channel length, W is the channel width, and g m = d I ds /d V g is the transconductance . Due to the synergistic effect of graphene and h-BN, our MoS 2 /h-BN/graphene vdW heterojunction transistor achieves the highest electron mobility of 340 cm 2 /(V·s) at room temperature .…”

Can 2D Semiconductors Be Game-Changers for Nanoelectronics and Photonics?

“…Thus, improving the response time for 2D photodetectors needs to be a priority moving forward. Parasitic circuit elements such as large contact resistance and junction capacitance are primary points of improvement and continue to be a research focus of the field. − …”

“…Efforts have been made to improve the response time via engineering device architecture from vertical homo- and heterojunctions to mixed-dimensional heterostructures. ,,, However, the improved operation speed comes at the cost of reduced photoresponsivity. Thus, improving both responsivity and response time for 2D photodetectors needs to be a priority moving forward, with large contact resistance, junction capacitance, and mobility as primary points of improvement, and needs to continue to be a research focus of the field. − …”

Newly Synthesized High‐k Polymeric Dielectrics with Cyclic Carbonate Functionality for Highly Stability Organic Field‐Effect Transistor Applications

“…The temperature and humidity can greatly influence the electrical properties of the polymer dielectrics and further impact the performance of flexible OFETs. [10,[34][35][36] Thus it is very necessary to investigate the thermal and humidity stability of flexible OFETs with polymer dielectrics.…”