The Characteristics of Silica Nano-powder and Thin Films Prepared from Rice Husk Ash

Abstract

In this study we have conducted laboratory research on the characteristics of silicanano-powder andthin films prepared from rice husk ash by extractionmethod. Rice husk ash was obtained fromAcehBesar district, Aceh province, Indonesia. The extraction process was carried out using 1.5% KOH and 10% HCl solution. The deposition of SiO 2 thin films was carried out by sol-gel method. SiO 2 thin films were grown on a glass substrate by a dip coating technique. The precursor solution was prepared by dissolving 1 gram of silica nano-powder into 20 ml of ethanol and stirring for 60 minutes at 50 0 C using a hot plate stirrer. The SiO 2 thin films were then annealed at various temperature of 450 - 600 0 C with a holding time of 60 minutes. XRD pattern showed that silica powder from rice husk ash has a nano-crystal structure. We found that there are other peaks besides SiO 2 . This indicated that silica nano-powder obtained by extraction method was still contains impurity elements. The characteristics of SiO 2 thin films strongly depend on annealing temperature. The optical bandgap of SiO 2 thin films varies from 3.63 - 3.68 eV.