Effect of Etching Time on Sensing Behavior of Porous Silicon Prepared by Electrochemical Method

Abstract

In the current work, porous silicon (PS) was prepared using an electrochemical etching process in a solution of hydrofluoric acid (HF) and ethanol (C₂H₅OH) at constant current density and various etching times using p-type silicon with a (100) orientation and resistivity of 8 Ω.cm. The structural and topographical characteristics of the prepared samples were introduced by the x-ray diffraction patterns and atomic force microscopy. Also, the sensing characteristics of the prepared samples to ammonia gas vapor was introduced. Cubic structure was confirmed in all porous samples. The PS layer on the silicon wafer was growing and the grain size within this layer was increasing with etching time. Average roughness, root-mean-square roughness, photoluminescence peak intensity, and a minor shift to higher frequency (blue shift) were increased with decreasing average grain size.