Surface topography and enhanced photo detecting properties of multilayer MoSe2 crystal

Abstract

The high photo responsive property and flexibility of tailoring the optical properties of the semiconducting layered transition metal dichalcogenides are appealing and makes them potentially suitable for the optoelectronic and photo detecting applications. In the present study molybdenum, diselenide (MoSe2) crystals were grown by direct vapor transport (DVT) technique in a dual zone horizontal furnace. To affirm the elemental composition and stoichiometric proportion of the as grown crystals, energy dispersive analysis of the x-ray was adopted. The surface morphological features of the grown crystals were investigated using light microscopy and scanning electron microscopy that attested the multilayer growth of crystals. The presence of single-crystalline phase and hexagonal structure was ascertained by employing transmission electron microscopy. The direct optical energy band gap of 1.42 eV was determined by UV-Visible spectroscopy. The Raman spectroscopy analysis carried out on the grown crystals revealed the presence of an A1g mode of vibration. Photo-detecting properties of the multilayer MoSe2 crystals were studied by exposing the basal plane of the photo-detecting sample by the polychromatic source of 70 mW/cm2 intensity at different biasing voltages from 1 V to 5 V respectively. The eminent sensing properties of the grown multilayered crystals are unveiled by the high photo responsivity 58.2 mA/Wm2 and specific detectivity 2.12 × 107 Jones. The effect of biasing voltage was prominently seen in the rise of photocurrent and detecting properties MoSe2 crystals.