| dc.description.abstract | Porous silicon structures are fabricated by electrochemical etching of silicon crystals. During the etching process, nanoscale silicon grains emerge, inducing the quantum confinement effect. This effect leads to significant alterations in the optical properties of silicon. In this work, we will investigate the photoluminescence and Raman scattering spectra of porous silicon structures at different etching depths. Additionally, we will attempt to provide more analysis of the spectral results.
In the Raman spectra, there are discernible differences between silicon crystals and porous silicon. The Raman signal of porous silicon exhibits shifts, asymmetry, and broadening of full-width at half-maximum (FWHM), which may also arise from the influence of quantum confinement effect. In our paper, we employ a 3D phonon confinement model to fit the size of silicon nano-crystals in porous silicon based on our experimental results of the Raman signal. Photoluminescence spectra can also be utilized to determine the size of silicon nano-crystals. In this work, we select seven different positions on the same sample and conduct spectral measurements at various etching depths at each position. Through spectral results, we can further determine the etching depth of the porous silicon. Additionally, we can obtain the spectral results of porous silicon at different etching depths and use these results to determine the size and crystalline quality of silicon nanocrystals. Three samples of porous silicon were fabricated using different etching current limits, and based on the spectral results, we assess the influence of etching current magnitude on the optical properties of porous silicon. | en_US |