Near-infrared photodetector based on the surface modification of porous silicon with silver nanoparticles

Abstract

This study describes the modification of Porous silicon (PS) by depositing commercial Ag powder on its surface and within its pores to improve its physical properties and performance as a near-infrared (NIR) photodetector. The incorporation of Ag-nanoparticles (Ag-NPs) into the PS structure increases the energy band gap from 1.74 eV to 2.46 eV and decreases the diffuse reflectance over a broad range of wavelengths. Afterward, NIR photodetectors of both structures are produced. The maximum current is measured at 850 nm for both photodetectors. In addition to a substantial decrease in the dark current of PS-Ag, PS-Ag's photo-excited current is 4.5 times greater than its dark current, whereas PS's photo-excited current is only 1.7 times greater. In addition, the I–V curves are used to determine the photodetector's sensitivity (S) and the current gain (G) at different incident light wavelengths. At wavelengths of 850 nm, the Au/PS-Ag/Au photodetector exhibits a greater sensitivity of 3.26 × 102 compared to the Au/PS/Au photodetector, which exhibits a sensitivity of 0.83 × 102. Based on the results, it is clear that modifying the PS with Ag-NPs is a strong candidate for excellent performance as a near-infrared photodetector in commercial photoelectronic device applications.