An investigation of photo_electrical properties of silicon nanoparticles/PSi/p-Si hetero structures

Abstract

In this work, two forms of nanocrystalline, were used (as-prepared macroPorous silicon and silicon nanoparticle) to synthesize hybrid structures for photodetectors applications. The fabrication pathway was carried out through two 2-steps processes. The 1-step was formation of as-prepared silicon nanoparticle (SiNPs), while and the 2-step was creation of low spam of macroPSi size substrate via electrochemical etching process in HF solutions. Specific features of SiNPs and low spam of macroPSi size substrate were explored using scanning electron microscopy SEM, energy-dispersive x-ray (EDX), Atomic Force Microscope (AFM), and photoluminescence (PL) spectroscopy respectively. Dark and photo current characteristics and spectral responsively of photodetectors were investigated for the macPSi layer and the hybrid structure. The performance of the hybrid configuration shows an improvement in the sensitivity of about 0.75 A/W with appearance of new additional peak at 450 nm as compared with the PSi photodetector of about 0.93 A/W. The achieved improvement is related with the appearance of double Heterojunction device between PSi/si and SiNPs/PSi. Also this improvement may be related with the reduction of the reflectd light from the hybrid structure due to the multiple reflection between SiNPs/PSi. The quantum efficiency η of the photodetector in the spectral range 450–700 nm was found to be 65%.