Fabrication and photodetection performance evaluation of nanostructured CdS/Si MSM visible light photodetector

In this manuscript, a series of nanostructured CdS/Si layers were fabricated through combined pulsed laser deposition (PLD) and thermal treatment techniques for visible light MSM photodetector application. The microstructural and optical characteristics of the deposited CdS layers as well as a systematic photodetection mechanism of the fabricated photodetectors were investigated as a function of laser parameters. In detail, the optical bandgap exhibited an alteration of 0.1 and -0.05 eV as the laser energy and wavelength increased from 140 to 220 mJ and 532 to 1064 nm, respectively. In conjunction, the proposed devices delivered photoresponsivity of 48 and 23 mA/W using laser energy of 140 and 220 mJ at 532 nm, while device fabricated using laser parameters of 220 mJ and 1064 nm demonstrated a value of 25 mA/W; the external quantum efficiency revealed values of 56, 113, and 59, respectively. The addressed photodetection characteristics were attained using a light source of 530 nm and 10 mW/cm2, whereas higher/lower light source wavelength demonstrated considerably lower figure of merits. Of the fabricated devices, photodetector achieved using laser parameters of 220 mJ and 532 nm exhibited ultra -fast response/recovery time of 112 and 119 ms, respectively, with radical stability profile.