Ultrasensitive Multilayer MoS₂‐Based Photodetector with Permanently Grounded Gate Effect

Abstract

chemical doping, elemental doping, and electrostatic gating techniques. The photoresponsive performances of PN-junction photodiodes have thus been effectively increased compared to intrinsic 2D material-based photodiodes. [18,19] Although PN-homojunction photodiodes exhibit better optical properties than intrinsic 2D materials photodiodes, there are many challenges present in fabricating the junctions. Chemical doping techniques are highly dependent on environmental conditions, [12,13] the elemental doping method causes limited vertical junction formation which leads to lower charge mobility, [5] and the electrostatic doping method has led to devices with slow photoresponses. [14] Heterojunction photodiodes with dissimilar materials and unequal bandgap have also been studied, using MoS 2 /Si, [20,21] MoS 2 /GaN, [22] MoS 2 / graphene, [23,24] MoS 2 /Black Phosphorous (BP), [6,25] and MoS 2 /pentacene, [26,27] and show improved electrical and optical properties compared to homojunction photodiodes. However, despite notable performance improvements in terms of photoresponsivity and sensitivity, homo-and heterojunction photodiodes are limited by low carrier mobility, difficult processing techniques, and unstable photoresponsive behavior. [18,19] In these designs, the chosen fabrication technique also has a significant influence on the device performance.Many studies have also been reported on Schottky barrier phototransistors, which incorporate a gate terminal to a metal-semiconductor-metal (M-S-M) design to obtain reliable electrical and optical properties along with a stable photoresponse and easier processing methods. [28,29] The gating effect is a key device function in these devices as it tunes the Schottky barrier, which controls charge transfer in the device. [30,31] The forward and reverse saturation currents can be determined by modulating the Schottky barrier by applying positive, negative, or zero bias. [28] However, electrical characteristics are often limited by the interface properties of the materials used, and more generally by fabrication techniques. The investigation of the Schottky contact between metals and MoS 2 is now gaining interest due to possible applications in photodetectors, biosensors, photovoltaics, as well as field-effect transistors (FETs).In this work, we introduce a unique design for MoS 2 photodiodes. This design uses a multilayer MoS 2 semiconductor layer 2D materials, specifically MoS 2 semiconductors, have received tremendous attention for photo-sensing applications due to their tunable bandgap and low noise levels. A unique photodetector using multilayer MoS 2 as the semiconductor channel, in which the gate electrode of the device is permanently connected to the grounded source electrode to introduce rectification, is reported. The proposed grounded-gate photodiode exhibits high photoresponsivity of 1.031 A W −1 , excellent photodetectivity (>6 × 10 10 jones), and highly stable rise/fall time response (100-200 ms) under illumination of visible light (at the wavelengths of 405,...

Lattice Defect Engineering Enables Performance-Enhanced MoS2 Photodetection through a Paraelectric BaTiO3 Dielectric

“…As a result, the energy barrier is sufficiently sharp to allow for the tunnelling current transport as photocurrent under reverse bias, while those in forward bias are sufficiently wide to prevent thermionic current but immune from photocurrent. 20 Figure 4b shows the value (I ph ) of the photocurrent minus the dark current dependence on the light power intensities (P) at V DS = −1 V. The curve follows a power law, I ph ∝ P θ , where θ is relative to the trap states at the MoS 2 /BTO interface. This provides a linear fitting on I ph − P, yielding θ = 0.999, which is very close to 1, indicating that the trapping/detrapping for the interfacial photogenerated carriers is negligible in the photocarrier collection.…”

“…Moreover, these strategies have been primarily explored via the MoS 2 field-effect-transistor (FET), rendering the electrostatic modulation much more promising, and they are popularly adopted because of its flexibility and doping tunability without breaking the structural integrity. After extensive exploration, it has been concluded that the gate dielectric in the case of electrostatic modulation crucially determines the FET performance, which has thus been intensively studied with the goal of optimizing the optoelectronic performance. , However, the gate dielectrics typically used in this scenario, such as those based on the capacitive coupling effect (SiO 2 , Al 2 O 3 ) , and/or interfacial configuration (hBN, BeO), play a singular role of insulating the gate leakage and are hindered by their rather low dielectric constant. Several attempts have been made recently using a relatively large dielectric constant, such as the study by Wang et al where poly­(vinylidene fluoride-trifluoroethylene) (P­(VDF-TrFE)) was utilized to enable rearrangement of the lattice atoms to greatly improve the carrier depletion; however, the highly efficient photocurrent and photoresponse were plagued by the large residual polarization, strong hysteresis, limited reduction in the bandgap, and structural and thermal instability of the polymers.…”

Highly sensitive active pixel image sensor array driven by large-area bilayer MoS2 transistor circuitry

“…Two-dimensional (2D) transition metal dichalcogenides (TMDs) such as molybdenum disulfide (MoS 2 ), molybdenum diselenide (MoSe 2 ), tungsten disulfide (WS 2 ), and tungsten diselenide (WSe 2 ) have been extensively studied as next-generation semiconducting materials due to their attractive electrical and optical properties 1 – 9 . However, although the TMD flakes obtained via mechanical exfoliation exhibit unique properties, their use in large-scale practical applications is difficult due to their low reproducibility and large property variations 10 – 17 . By contrast, various large-area growth methods for 2D TMDs have been developed for future electronic and photonic applications 18 – 25 .…”

Low‐Temperature Carrier Transport Mechanism of Wafer‐Scale Grown Polycrystalline Molybdenum Disulfide Thin‐Film Transistor Based on Radio Frequency Sputtering and Sulfurization

“…Molybdenum disulfide (MoS 2 ), one of the most well-known transition metal dichalcogenides, is an attractive candidate for future electrical and optoelectrical applications. [1][2][3][4][5][6][7][8] More specifically, MoS 2 has excellent electrical properties, a suitable bandgap (E g = 1.2-1.9 eV), excellent fieldeffect mobility (μ FE ) at room temperature (RT) (μ FE = 100 cm 2 V -1 s -1 ), and a low subthreshold swing (SS = 70 mV decade -1 ). [9][10][11] It also has other intriguing properties such as high photoresponse and the absence of dangling bonds.…”