Porous Silicon Sensors- Elusive and Erudite

Abstract

Porous Silicon Sensors have been fabricated and tested successfully over the last few years as humidity sensors, vapour sensors, gas sensors, piezoresistive pressure sensors and bio-sensors. In each case it has displayed remarkably sensitivity, relatively low temperature operation and ease of fabrication. Brief description of fabrication and properties of all these types of different sensors is reported in this paper. The barriers of porous silicon like contact, non-uniformity, instability etc. are also discussed.

Porous silicon gas sensors

“…Gas molecules in a PSi-based gas sensor are adsorbed on the surface of the PSi layer and diffuse into the porous bulk. Condensation of the diffused gas may occur inside pores that have radii less than a critical value called the 'Kelvin radius' (Saha, 2008).…”

“…A theoretical model was proposed by Saha (2008) in order to explain the change in the dielectric constant of the PSi layer and to provide a theoretical basis for optimizing the porosity and pore morphology of the PSi layer. This model considers PSi as a three-phase mixture of dispersed spherical particles consisting of silicon nano-particles, silicon oxides and voids.…”

“…The detection and quantifi cation of bacterium, viruses and other organic materials, including DNA, measured by PSi sensors have been reported (Saha, 2008;Miller, 2012). The properties of gas sensors will be discussed below.…”

“…Calculations of the refl ectance of such PSi coatings have been carried out (Aroutiounian et al ., 2004;2006a;2006b;2007;2008;Martirosyan et al ., 2007) using the optical matrix approach method. Dramatically lower refl ectance within a larger energy range that includes the ultraviolet, visible and infrared regions of the solar spectrum can be realized in the case of diamond-like carbon (DLC)/PSi and silicon oxynitride/PSi double layers, as proposed by the authors, during comparison with the spectra obtained that are usually used in SiO 2 /TiO 2 ARC solar cells.…”

Study the Characteristic of Planer and Sandwich PSi Gas Sensor (Comparative Study)

“…Has been detection many of organic materials, including DNA, measured by PSi sensors have been reported. Aroutiounian [1][2][3]. PSi can be considered as a Ministry of Science and Technology, Baghdad, Iraq silicon crystal having a network of voids in it.…”