Structural and Optoelectronic Parameters of a Cobalt-Doped Molybdenum Disulfide Diode-Based Photodetector

This study investigated the structural, electrical, and optical properties of MoS₂ and Co-doped MoS₂ nanosheets, focusing on their potential applications in optoelectronics. High-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), current-voltage (<i>I</i>-<i>V</i>), and ultraviolet-visible (UV-vis) spectroscopy were used to examine the materials. Results indicate that Co-doping enhances the active sites for more light absorption, reduces the bandgap, and improves photoconductivity. The diode characteristics from <i>I</i>-<i>V</i> measurements were also analyzed. The <i>I</i>-<i>V</i> showed typical diode-like rectification behavior with great improvement in key parameters like the ideality factor (<i>n</i>), saturation current (<i>I</i> _s), and junction resistance (<i>R</i> _j) of the Co-doped device. The photodetector based on the Co-doped device exhibited superior photocurrent (<i>I</i> _photo) generation, responsivity (<i>R</i>), and detectivity (<i>D</i>*) compared to the MoS₂ device, indicating its enhanced photodetection performance. These results show that Co-doping significantly improves the efficiency of photon-to-electron conversion, making the MoS₂-Co device much more efficient in harvesting light energy.