Effect of vanadium doping on the photo response ability of hydrothermally prepared 2H-MoS2

Abstract

The present study demonstrates the synthesis of vanadium (V)-doped MoS2 nanomaterials with V concentrations ranging from 1% to 7% using a straightforward hydrothermal technique. The impact of V doping on the structure, optoelectronic characteristics, surface chemistry, and photoresponse was studied by closely analyzing the atomic structure, surface morphology, and elemental composition. The underlying hexagonal lattice of MoS2 is unaffected by the increasing concentrations of dopants, although there are slight variations in the diffraction peaks with different intensities that point to defects and lattice distortions. Changes in the crystal’s electrical environment are demonstrated by the variations in signal location and strength. The x-ray photoelectron spectroscopy data, which display unique peaks for Mo, S, and V and prove that V atoms directly replace Mo atoms inside the crystal lattice, provide evidence of the elements’ chemical states. Analysis of diffuse reflectance spectra UV–vis spectroscopy of the samples shows an increase in absorption and a gradual reduction in bandgap energy from 2.90 eV (undoped MoS2) to 2.82 eV (7% V-doped MoS2). Analysis of the photodetector results shows linear and symmetric I–V characteristics in dark and illuminated conditions. V doping significantly enhances photocurrent, responsivity, and photosensitivity, with the best results at intermediate doping levels. Analysis of the I–T curve of the photoresponse characteristics shows good light ON/OFF switching with rise and fall times of 17–23 s, thus confirming the functionality of the device. Although the overall photoresponse is restricted by the substrate and experimental limitations, the study clearly establishes the significance of V doping in modifying the optoelectronic properties of MoS2.