An efficient multispectral CsSnI₃ MSM photodetector using back grooves and light trapping optimization: FDTD-GA calculations

The present work aims at developing a new design strategy based on optimizing light trapping management in the CsSnI₃ perovskite active layer using back groove engineering, to tune the broadband photoresponsivity. To do so, an extensive numerical simulations based on 2D-Finite Difference Time Domain (FDTD)-SILVACO calculations are carried out to assess the optoelectronic properties of the proposed sensor, including the impact of back grooves engineering. The effect of the groove geometry on the photosensing characteristics of the photodetector (PD) is analyzed. It is found that the depth, width and the period of the back grooves can modulate the optical behavior of the CsSnI₃ perovskite active layer, showing a great potential for improving the light harvesting capabilities over a wide spectral range. A Genetic Algorithm Optimization (GAO) technique is implemented to find out the best groove geometry and period, offering the highest photoresponse over UV to NIR spectral bands. The obtained results show the ability of the proposed strategy to improve and tune the optoelectronic properties of the device, demonstrating a high responsivity of 78 mA/W and an improved I_ON/I_OFF ratio of 61 dB. Therefore, the proposed approach can open new paths to enhance the optical and electrical performances of thin film perovskite photodetectors by optimizing the light trapping management using back groove engineering and metaheuristic calculations.