Investigation of variation of porous silicon structure using metal-assistedchemical etching

Metal-assisted etching procedure is an inexpensive, easy, and efficient method to create porousstructures which are the potential candidate in photovoltaic industry [1]. Porous structures due totheir great applications in optoelectronics, sensors, solar cells has been attracted great attentions[2-5]. In this research metal-assisted etching of silicon in HF/H2O2/H2O mixture wasinvestigated by using Ag nanoparticles as catalyst agents. So we changed the concentration ofH2O2 relative to HF to creation of various structures and characterization of their properties suchas anti-reflection properties. FE-SEM images and etch rate measurements were performed as afunction of the etching solution mixture. Depending on the relative amount of HF and H2O2,different morphology and structures were resulted. The molar ratio of HF, H2O2 is given intable1. The XRD analysis was done to investigate the structure formation and found that thesample which is immersed into an aqueous solution of HF/H2O2 and molar ratio (7/0.88) has thebest porous structure and shows that the sample3 has a structure similar to the free single crystalwafer because of its peak is sharp and has high intensity. The anti-reflection properties of porouslayer was investigated to trapping the sun light and found that the sample2 is the most appropriateone.

Keywords:

Silver nanoparticles , HF–H2O2 solutions , Assisted etching , Porous silicon