New high performance ultraviolet (MSM) TiO2/glass photodetector based on diffraction grating for optoelectronic applications

In this paper, a new TiO2-based UV photodetector including back triangular texturization morphology has been investigated numerically using accurate solutions of Maxwell's equations. A quantitative study of the device optical parameters like responsivity, sensitivity, detectivity, derived current capability and signal to noise ratio have been carried out in order to review the device overall optical performance for UV optical communication applications. Based on the obtained results, we have found that the device performance figures-of-merit (FoMs) governing the optical behavior is strongly improved as compared to its conventional planar counterpart, where the proposed design offers superior photocurrent, higher responsivity and sensitivity in comparison with those provided by the planar structure. These results led us to suggest the optimization of the proposed morphology using genetic algorithm (GA), in order to improve the electric field confinement and UV-light trapping in TiO2 absorber layer, where excellent ability has been recorded in enhancing the device absorbance. In this context, photodetector with optimized triangular texturization exhibits a 432% improvement, in term of responsivity, over planar structures and 120% improvement over the textured device without optimization. Thus, these encouraging results make the proposed device an extremely efficient candidate for high performance optoelectronic applications.