Improvements in the Performance of a Visible-NIR Photodetector Using Horizontally Aligned TiS₃ Nanoribbons

We report the fabrication and characterization of visible and near-infrared-resistive photodetector using horizontally aligned titanium tri sulfide (TiS₃) nanoribbons. The fabrication process employed micro-electromechanical system, photolithography and dielectrophoretic (DEP) methods. The interdigitated electrodes (IDE) fingers were fabricated using photolithography and thin-film metallization techniques onto the Si/SiO₂ substrate, and then TiS₃ nanoribbons were horizontally aligned in between IDE using DEP. The fabricated device was first characterized in absence of light and then, the photodetector-based characteristics were obtained by illuminating it with fiber-coupled laser beam. These characteristics were optimized by varying wavelength and power density of the laser beam. The present photodetector shows a maximum responsivity of 5.22 × 10² A/W, quantum efficiency of 6.08 × 10², and detectivity of 1.69 × 10⁹ Jones. The switching times, i.e., response and recovery times were found to be 1.53 and 0.74 s, respectively, with 1064 nm wavelength and 3.4 mW/mm² power density of the laser beam. Also, the effect of O₂ adsorption on nanoribbons has been studied and it is found that adsorbed O₂ acts as electron acceptor and decreases the conductivity of the photodetector. Experimentally, it is found that the photoresponse of the horizontally aligned TiS₃ nanoribbons is better than that of a randomly oriented TiS₃ nanoribbon-based photodetector. Finally, the performance of the present photodetector was compared to that of the previous ones that were found to outperform the reported ones. The additional advantages of the photodetector include excellent stability and portability from which it may be concluded that TiS₃ nanoribbons can be a promising candidate for application in nanoscale electronic and optoelectronic devices.