The effect of etching time on structural properties of Porous silicon at the room temperature

Abstract

Nano-porous silicon (PS) layers have been prepared by electrochemical etching of (100) silicon wafer in the solution of hydrofluoric acid (HF) and ethanol (C2H5OH). In this paper, XRD and FTIR confirm the formation of PS. The size of crystallites in the porous Si layers was found from XRD, which isaround ~2.4 nm. The evolution of morphology of PS as a function of etching time is imaged using SEM. The average pore-diameter has been calculated from the image j software, which is in the range of 238-1117nm. The Raman spectra reveal that the peak intensities sharply increase with etching time due to presence of nancrystals on the surface of PS. It was observed that the peak of Raman signal was around ~520.5cm-1. Luminescence studies revealedthat the strong photoluminescence emission was observed at about ~660nm. It possesses a broad red emission band on the surface of PS due to the growth of Si=O bonds and the formation of silicon hydrides (SiHx), which is caused to trapped electron states at the interface between the crystalline Si and SiO2. � 2016 Elsevier Ltd.