In this paper, we report on the fabrication and optoelectronic properties of high sensitive phototransistors based on few-layered MoSe2 back-gated field-effect transistors, with a mobility of 19.7 cm² V⁻¹ s⁻¹ at room temperature. We obtained an ultrahigh photoresponsivity of 97.1 AW⁻¹ and an external quantum efficiency (EQE) of 22 666% using 532 nm laser excitation at room temperature. The photoresponsivity was improved near the threshold gate voltage; however, the selection of the silicon dioxide as a gate oxide represents a limiting factor in the ultimate performance. Thanks to their high photoresponsivity and external quantum efficiency, the few-layered MoSe2-based devices are promising for photoelectronic applications.

In recent years, the integration of two-dimensional (2D) nanomaterials, especially transition metal chalcogendies (TMCs) and dichalcogendies (TMDCs), into electronic devices have been extensively studied owing to their exceptional physical properties such as high transparency, strong photoluminescence, and tunable bandgap depending on the number of layers. Herein, we report the optoelectronic properties of few-layered MoSe 2 -based back-gated phototransistors used for photodetection. The photoresponsivity could be easily controlled to reach a maximum value of 238 AW −1 under near-infrared light excitation, achieving a high specific detectivity D 7.6 10 cm Hz W .Few-layered MoSe 2 exhibited excellent optoelectronic properties compared with those reported previously for multilayered 2D material-based photodetectors, indicating that our device is one of the best high-performance nanoscale nearinfrared photodetectors based on multilayered two-dimensional materials.

Two-dimensional (2D) layered materials exhibit unique optoelectronic properties at atomic thicknesses. In this paper, we fabricated metal-semiconductor-metal based photodetectors using layered gallium selenide (GaSe) with different thicknesses. The electrical and optoelectronic properties of the photodetectors were studied, and these devices showed good electrical characteristics down to GaSe flake thicknesses of 30 nm. A photograting effect was observed in the absence of a gate voltage, thereby implying a relatively high photoresponsivity. Higher values of the photoresponsivity occurred for thicker layers of GaSe with a maximum value 0.57 AW(-1) and external quantum efficiency of of 132.8%, and decreased with decreasing GaSe flake thickness. The detectivity was 4.05 × 10(10) cm Hz(1/2) W(-1) at 532 nm laser wavelength, underscoring that GaSe is a promising p-type 2D material for photodetection applications in the visible spectrum.

We report on the exponential decay of the red-shift of the photoluminescence A-exciton peak in monolayer molybdenum disulfide (MoS2) with the excitation laser power. The linear relationship found for the thermal variation of the same peak suggests that the laser power effect goes beyond the exciton dynamics associated to temperature variations. Laser exitation power effect on the broadening and red-shifting of the A(1g) and E(2g)1 phonon peaks observed by Raman spectroscopy reflect the damping of vibration due local thermal heating induced by the laser. Our results point out the laser excitation power dependence on the photoluminescence properties of monolayer MoS2.

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We describe the fabrication and magnetoelectric properties of robust, high sensitivity Hall effect sensors fabricated using AlGaN/GaN and AlInSb/InAsSb/AlInSb heterostructures with a two-dimensional electron gas at the heterointerface. The sensitivity of AlInSb/InAsSb/AlInSb heterostructure clearly degrades above C. The AlGaN/GaN 2DEG Hall sensors were stable up to at least 400 C and even after irradiation of 380 keV protons with a fluence of cm , where AlInSb/InAsSb/AlInSb heterostructure showed an increase in the sheet carrier density. The feasibility of applications of the AlGaN/GaN and AlInSb/InAsSb/AlInSb Hall sensor for harsh radiation environment is discussed.

Two-dimensional (2D) materials are promising for future electronic and optoelectronic devices. In particular, 2D material-based photodetectors have been widely studied because of their excellent photodetection performance. Owing to its excellent electrical and optical characteristics, 2D indium selenide (α-In2Se3) is a good candidate for photodetection applications. In addition, α-In2Se3 samples, including atom-thick α-In2Se3 layers, present ferroelectric properties. Herein, we report the fabrication and electrical and optoelectronic properties of multilayered graphene (Gr)/α-In2Se3/Gr-based ferroelectric semiconductor eld-effect transistors (FeS-FETs). Furthermore, we discuss the physical mechanisms affecting electronic and optoelectronic transport in the Gr/α-In2Se3/Gr heterostructure. Large hysteresis was observed in the transfer characteristic curves and it was attributed to the ferroelectric polarization of MTL α-In2Se3 and carrier trapping-detrapping effects. The optoelectronic performance of the fabricated FeS-FETs depended on the ferroelectric properties of α-In2Se3 and can be easily tuned to achieve the maximum photoresponsivity and speci c detectivity of 10 AW-1 and 4.4 × 1012 cmHz1/2W-1, respectively.