High Temperature Carrier Scattering Mechanisms in Multilayer ReS₂ Field-Effect Transistors

Abstract

Electrical conductivity (σ) indicates the efficiency of current flow through electronic materials, and varies with both carrier density (n 2D ) and mobility (𝜇). Studying the temperature-dependent σ of a material allows for the elucidation of various carrier transport mechanisms such as metal-insulator phase transition, Coulomb impurity scattering, metal-semiconductor barrier, and quantum tunneling features. Herein, we report a considerable interlayer resistance (R IT ) effects on the carrier scattering mechanism occurring in a multilayer rhenium disulfide (ReS 2 ) transistor, particularly at high temperatures. At room temperature (T = 300 K), a channel centroid gradually migrates from the bottom to the top surface of ReS 2 multilayers by contributing to the suppressed R IT with increasing electrostatic drain (V D ) and gate (V G ) bias conditions. Meanwhile, for temperatures above 380 K, the effective interlayer resistance quickly decreases with increasing V G , and the ReS 2 multilayer consequently demonstrates an anomalous carrier mobility enhancement. For a better insight into the charge scattering mechanism, the obtained temperature-dependent carrier mobility was further analyzed by employing Matthiessen's rule for Coulomb impurity scattering, phonon scattering, and interlayer resistance scattering, respectively. Our study would shed light on deep understanding for the high temperature carrier scattering mechanism and further improvements in diverse optoelectronic applications of ReS 2 multilayers.

Enhanced Interlayer Charge Injection Efficiency in 2D Multilayer ReS2 via Vertical Double-Side Contacts

“…The optical Raman spectrum of the fabricated ReS 2 multilayer measured using confocal Raman microscopy with a laser excitation wavelength (λ EX ) of 532 nm at a power ( P ) of 500 μW is presented in Figure d. The dominant vibrational modes of E g -like (≈132, 143 cm –1 ) and A g -like (≈152, 161, 213 cm –1 ) peaks are clearly observed, indicating 1T′ multilayer ReS 2 , which is consistent with previous reports. ,,, …”

“…The dominant vibrational modes of E g -like (≈132, 143 cm −1 ) and A g -like (≈152, 161, 213 cm −1 ) peaks are clearly observed, indicating 1T′ multilayer ReS 2 , which is consistent with previous reports. 19,28,36,37 The gate bias (V G )-dependent drain current−voltage (I D − V D ) output characteristics of TC, BC, and VDC measured at L 2 (=2 μm) are displayed in Figure 2a. To directly compare the electrical properties of the ReS 2 multilayer with respect to different contact configurations, VDC measurements were performed by connecting the BNC cables for the TC and BC via a BNC tee connector.…”

Negative Differential Interlayer Resistance in WSe2 Multilayers via Conducting Channel Migration with Vertical Double-Side Contacts

“…Notably, two transconductance humps appear in the small V D regime ( V D < 0.5 V) regardless of the contact configuration. This implies the presence of two conducting mechanisms or conducting paths. − , The first observed hump has been ascribed to the formation of the bottom channel by taking the Thomas–Fermi charge screening theory for our back-gated device configuration into account. Meanwhile, the second hump has been interpreted as the formation of the top channel by attributing it to the suppressed interlayer resistance driven by the electrostatic V G and V D .…”

“…In the presence of electrostatic bias-dependent interlayer resistance, previous studies have described the complex carrier transport of 2D multilayers by taking the Thomas–Fermi charge screening length and thickness-dependent carrier mobility into account. , For example, in a conventional back-gate configuration, a layer exhibiting the highest conductivity among layers shifts toward the top surface from the bottom surface because of an interplay between the interlayer resistance and the layer-dependent in-plane carrier mobility. This triggers a spatial redistribution of charge carriers along the thickness. − Additionally, a vertical double-sided contact configuration has recently been demonstrated to be a preferable platform for evaluating the spatial modification and separation of the conducting channel within 2D vdW multilayers by comparing the obtained drain current with respect to bottom contact and top contact, respectively . Nevertheless, this distinct transport feature would be masked substantially by undesired chemical residues, surface adsorbates such as oxygen and water molecules, and contact resistance. − This would obstruct the attainment of clear insight into the carrier transport behavior of 2D vdW multilayers, particularly for the variation of the channel vertical position under electrostatic drain and gate bias conditions.…”