Authors : Alwan M. Alwan, Muslim F. Jawad and Duaa A. Hashim
Abstract: In this research, normal Porous Silicon PSi layers and Gradient-Porous Silicon GPSi layer modified with Pd nanoparticles was used to produce an effective gas sensor. PSi and GPSi were fabricated using Laser-Assisted Etching process (LAE) on n-type silicon substrate. In PSi layer a laser diode of 630 nm wavelength and illumination intensity of about 25 mW/cm2 at a fixed etching current density of 25 mA/cm2 was employed. A step-gradient current density ranging from 25 to 5 mA/cm2 at a fixed laser illumination intensity 25 mW/cm2 was used to prepare GPSi. The surface morphology of bare PSi and GPSi and modified with Pd NPs were examined using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), FTIR spectroscopy and EDS analysis. Electrical properties (J-V) of bare PSi, GPSi and modified with Pd nanoparticles were measured in vacuum and with CO2 pressures of (0.5 and 1mbar) at room temperature. The result showed that the nanoparticles sized and substrate morphology strongly affected the sensor performance. It was found that the sensitivity of the sensor with modified GPSi is twice than the sensitivity of PSi due to the high density of dangling bonds at the interface of the silicon matrix.
Alwan M. Alwan, Muslim F. Jawad and Duaa A. Hashim, 2019. Comparative Study: Co2 Sensing of Palladium Nanoparticles Grown on Normal and Gradient Porous Silicon. Journal of Engineering and Applied Sciences, 14: 5420-5428.