Effects of incorporating manganese in CdS thin films elaborated by CBD and the performance of Schottky diodes TCO/CdS:Mn/C

This study focuses on manganese doped CdS thin films by chemical bath deposition (CBD). Thin films and Schottky diodes of CdS and CdS:Mn are synthesized by a simple chemical route. The influence of the incorporation of Mn2+ cations in the crystalline structure of CdS has been characterized by techniques such as XRD, SEM, XPS, UV-Vis spectroscopy, and I-V curves. Doped thin films have a uniform hexagonal structure and preferentially grow along the (100) and (002) planes. The higher the amount of Mn2+ cations, the preferential orientation of the (100) plane gradually disappears, while the undoped sample shows a preferential orientation in the (002) plane. In addition, the morphology, when incorporating manganese, exhibits a drastic change, generating scale-like and needle-like structures, and the average size of the particles varies from 67 nm to 107 nm, in contrast to virgin CdS particles that show a mean size of 23 nm , spherical structures. The variation of the bandgap is 0.067 eV due to the presence of the preferential orientation in the specialIntscript crystal plane in the Mn-doped samples and the doping increase in crystallite size. Doped Schottky diodes exhibit a saturation current of 2 nA and a potential barrier of 0.66 eV, compared to undoped diodes that exhibit a saturation current of 0.93 nA and a potential barrier of 0.823 eV. In addition, it was possible to modify the rectification speed of the diodes by almost 70 % by incorporating manganese. Overall, our study reveals that there is great potential in the design of affordable high-speed optoelectronic devices, although we are aware that we are still at an early stage in achieving these goals.