Liquid-phase exfoliation of WSe2 nanosheets for ITO/WSe2 photodetector

The potential application of atomically thin two-dimensional (2D)-layered WSe₂ in future wearable electronics has sparked a lot of interest. Herein, we report the highly crystalline nature of WSe₂ nanosheets was synthesized by the liquid-phase exfoliation technique and its application as a broadband photodetector. The direct vapor transport (DVT) technique has been used in the synthesis of bulk WSe₂ compounds. The chemical composition and purity of the grown compound were investigated by EDAX (Energy-dispersive analysis of X-ray). The structural phase analysis and the crystalline orientation were examined by X-ray diffraction technique (XRD), Scanning electron microscopy (SEM), and High-resolution transmission electron microscopy (HR-TEM) of the synthesized WSe₂ compound. The Raman spectrum depicts the resonances corresponding to the E_2g mode of vibration of WSe₂ nanosheets. Additionally, a broadband photodetector based on WSe₂ nanosheets was constructed and evaluated under wavelength-dependent illumination sources with a power level of 40 mW/cm² on a 1.0 bias voltage. The ITO/WSe₂ nanosheet device was studied under the function of various power intensities and various external bias voltages. The device is tested for bias between 0 and 30 V and its responsiveness is improved. Furthermore, the device demonstrated higher stability under 40 mW/cm² intensity. The results showed that WSe₂ nanosheets have good optoelectronic capabilities and can be used in future optoelectronic devices.