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 E2g 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.