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P-type laser-doped WSe <sub/>2</sub> /MoTe <sub/>2</sub> van der Waals heterostructure photodetector
摘要: Van der Waals heterostructures (vdWHs) based on two-dimensional (2D) materials are being studied extensively for their prospective applications in photodetectors. As the pristine WSe2/MoTe2 heterostructure is a type I (straddling gap) structure, it cannot be used as a photovoltaic device theoretically, although both WSe2 and MoTe2 have excellent photoelectric properties. The Fermi level of p-doped WSe2 is close to its valence band. The p-doped WSe2/MoTe2 heterostructure can perform as a photovoltaic device because a built-in electric field appears at the interface between MoTe2 and p-doped WSe2. Here, a 633 nm laser was used for scanning the surface of WSe2 in order to obtain the p-doped WSe2. X-ray photoelectron spectroscopy (XPS) and electrical measurements verified that p-type doping in WSe2 is produced through laser treatment. The p-type doping in WSe2 includes substoichiometric WOx and nonstoichiometric WSex. A photovoltaic device using p-doped WSe2 and MoTe2 was successfully fabricated. The band structure, light-matter reactions, and carrier-transport in the p-doped WSe2/MoTe2 heterojunction were analyzed. The results showed that this photodetector has an on/off ratio of ≈104, dark current of ≈1 pA, and response time of 72 μs under the illumination of 633 nm laser at zero bias (Vds = 0 V). The proposed p-doping method may provide a new approach to improve the performance of nanoscale optoelectronic devices.
关键词: molybdenum ditelluride,heterojunction,tungsten selenide,photodetector,p-doped
更新于2025-09-23 15:21:01
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The Au/Cu2WSe4/p-Si photodiode: Electrical and morphological characterization
摘要: Cu2WSe4 nanosheets were synthesized by the hot-injection method and put as interfacial layers between Au metal and p-Si by spin coating technique to investigate their photoresponse and capacitor properties via I-V and C-V measurements, respectively. The XRD were operated to confirm crystalline structure of the Cu2WSe4. The TEM image revealed that the crystalline nanosheet structures of the Cu2WSe4. The I-V measurements were performed under dark and light illumination in the range 20 mWe100 mW light intensities with 20 mW interval. In addition, some diode parameters such as ideality factor, barrier height and series resistance were extracted via a various method and discussed in the details. The C-V measurements were employed for various frequency and voltages. The C-V characteristics of the device confirmed the strong dependence on the frequency and voltage. The results imparted that Au/Cu2WSe4/p-Si can be employed for photodiode, photodetector and capacitor applications.
关键词: Copper tungsten selenide,Photodetector,Schottky devices,Cu2WSe4,Au/Cu2WSe4/p-Si photodiode
更新于2025-09-10 09:29:36