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 SiO2 thin films was carried out by sol-gel method. SiO2 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 0C using a hot plate stirrer. The SiO2 thin films were then annealed at various temperature of 450 - 600 0C 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 SiO2. This indicated that silica nano-powder obtained by extraction method was still contains impurity elements. The characteristics of SiO2 thin films strongly depend on annealing temperature. The optical bandgap of SiO2 thin films varies from 3.63 - 3.68 eV.