Synthesis and characterization of SnO2/porous silicon hybrid nanostructures for gas sensing

Abstract

In this work, Tin oxide SnO2 hybrid structures were deposited on porous silicon substrates via spray pyrolysis method. The impact of the current density changes ranging from 5- 15 mA/cm2 with HF concentration of 18% was investigated at fixed substrate temperature of 250Co . The XRD analysis for nanostructures revealed the presence of tetragonal structure of SnO2. The Scanning electron Microscope (SEM) images showed the sponge-like structure of PSi with grooves and cavities following the deposition of SnO2 on the substrate. It can be seen, the grain diameter arrangement of the SnO2 was found to be in the range from 42–64 nm. The I-V characteristics showed that the resistance raises with the current density of the SnO2/porous silicon. The optical results refers that the absorption of SnO2 nanostructure increases with the number of spraying times for values of (10,15 and 20) respectively. Moreover, the results also revealed a degradation of the energy gap from 3.3 to 2.82eV at the same spraying values. The higher sensitivity was found around 49.35% at etching current density of 15mA/cm2 . The structure quality of the SnO2/PSi provides the possibility of using such structures in the high-quality sensors.