Barrier Formation at the Contacts of Vanadium Dioxide and Transition-Metal Dichalcogenides

Abstract

Phase-transition field-effect transistors (FETs) are a class of steep-slope devices that show abrupt on/off switching owing to the metal−insulator transition (MIT) induced in the contacting materials. An important avenue to develop phase-transition FETs is to understand the charge injection mechanism at the junction of the contacting MIT materials and semiconductor channels. Here, toward the realization of high-performance phase-transition FETs, we investigate the contact properties of heterojunctions between semiconducting transition-metal dichalcogenides (TMDCs) and vanadium dioxide (VO 2 ) that undergoes a MIT at a critical temperature (T c ) of approximately 340 K. We fabricated transistors based on molybdenum disulfide (MoS 2 ) and tungsten diselenide (WSe 2 ) in contact with the VO 2 source/drain electrodes. The VO 2 -contacted MoS 2 transistor exhibited n-type transport both below and above T c . Across the MIT, the on-current was observed to increase only by a factor of 5, in contrast to the order-of-magnitude change in the resistance of the VO 2 electrodes, suggesting the existence of high contact resistance. The Arrhenius analyses of the gatedependent drain current confirmed the formation of the interfacial barrier at the VO 2 /MoS 2 contacts, irrespective of the phase state of VO 2 . The VO 2 -contacted WSe 2 transistor showed ambipolar transport, indicating that the Fermi level lies near the mid gap of WSe 2 . These observations provide insights into the contact properties of phase-transition FETs based on VO 2 and TMDCs and suggest the need for contact engineering for high-performance operations.

Intelligent Off/On Switchable Microwave Absorption Performance of Reduced Graphene Oxide/VO2 Composite Aerogel

“…[33] This reversible transition with dramatic changes in electrical conductivity promises VO 2 a wide range of potential applications in optoelectronic, transistors, and antennas. [34][35][36] For the first time, we developed a VO 2 /reduced graphene oxide composite aerogel with excellent off/on switchable MA performance. As temperature increases, the VO 2 -based materials show the real-time phase change behavior.…”

Femtojoule‐Power‐Consuming Synaptic Memtransistor Based on Mott Transition of Multiphasic Vanadium Oxides

“…Notably, studies on the integration of VO 2 into various electronic devices, such as resistors, [ 19 ] resistive random access memory selectors, [ 20 ] and transistors, [ 21 ] have been reported. These studies demonstrate the unique functions of VO 2 ‐implemented devices, for example, the transition between non‐volatile and volatile memory effects; [ 22 ] abrupt subthreshold swing in metal‐oxide‐semiconductor field‐effect transistors; [ 23 ] and the fast response to various stimuli such as heat, bias, and light. [ 24,25 ] However, the practical application of Mott memory devices by using transition metal oxides, including VO 2 , requires further innovations to overcome several technical issues, such as difficulties associated with the deposition of single VO 2 phase thin films, reliable Mott transition of multiphasic VO x , and importantly, heat generation during device operation since it can adequate to destabilize VO 2 .…”

Phase Transition-Induced Temperature-Dependent Phonon Shifts in Molybdenum Disulfide Monolayers Interfaced with a Vanadium Dioxide Film

“…18 The MIT of VO 2 occurs abruptly on a timescale down to femtoseconds, along with resistance change properties up to the order of 10 5 . 15 Accordingly, VO 2 -contacted TMD transistors as an energyefficient concept of phase-transition field effect transistors for the realization of steep-slope transistors have been recently demonstrated. 16,17 In addition to abrupt resistance switching characteristics, VO 2 exhibits both thermal contraction and expansion for lattice parameters due to the SPT during heating and cooling cycles.…”

“…The recent progress in atomically thin two-dimensional (2D) transition-metal dichalcogenides (TMDs) beyond graphene has led to a variety of promising technologies for nanoelectronics, photonics, sensing, energy storage, energy conversion, opto-electronics, and spintronics because of solution processability and a unique combination of van der Waals interactions, tunable bandgaps, strong spin–orbit coupling, and favorable electronic/mechanical properties. − Furthermore, combining functional 2D TMD materials into heterostructures through hybrid integration with other materials, such as Si, GaN, , SiC, organic materials, and oxides, − has recently attracted increasing attention for exploring new physics and providing desirable multiple functionalities.…”

“…In particular, among materials interfaced with 2D TMDs, vanadium dioxide (VO 2 ) is a representative strongly correlated oxide material that undergoes a metal–insulator transition (MIT) coupled with a reversible first-order structural phase transition (SPT) between a high-temperature rutile (R) phase and a low-temperature monoclinic (M1) phase at a temperature of approximately 68 °C . The MIT of VO 2 occurs abruptly on a timescale down to femtoseconds, along with resistance change properties up to the order of 10 5 . Accordingly, VO 2 -contacted TMD transistors as an energy-efficient concept of phase-transition field effect transistors for the realization of steep-slope transistors have been recently demonstrated. , In addition to abrupt resistance switching characteristics, VO 2 exhibits both thermal contraction and expansion for lattice parameters due to the SPT during heating and cooling cycles.…”