Sensing Properties of Oxidized Nanostructured Silicon Surface on Vaporized Molecules

Abstract

Porous silicon has been intensely studied for the past several decades and its applications were found in photovoltaics, biomedicine, and sensors. An important aspect for sensing devices is their long–term stability. One of the more prominent changes that occur with porous silicon as it is exposed to atmosphere is oxidation. In this work we study the influence of oxidation on the sensing properties of porous silicon. Porous silicon layers were prepared by electrochemical etching and oxidized in a tube furnace. We observed that electrical resistance of oxidized samples rises in response to the increasing ambient concentration of organic vapours and ammonia gas. Furthermore, we note the sensitivity is dependent on the oxygen treatment of the porous layer. This indicates that porous silicon has a potential use in sensing of organic vapours and ammonia gas when covered with an oxide layer.

UV-light activated APTES modified WO3-x nanowires sensitive to ethanol and nitrogen dioxide

“…Thus, the higher sensitivity of the APTES@WO3-x sensors to ethanol may be influenced by the higher polarity of this analyte given its larger electronegative difference (ΔEN = 1.4 for ethanol) in the polar region compared to acetone (ΔEN = 1) and carbon monoxide (ΔEN = 1) [30]. The correlation of the sensitivity and the polarity of various reducing analytes has also been noticed in recent literature reports [31]. Similarly, the sensitivity to nitrogen dioxide could be connected with the polar nature of this analyte and the high sensitivity of tungsten oxide to electron acceptor (oxidizing) than electron donor (reducing) analytes [32].…”

How to Improve the Performance of Porous Silicon‐Based Gas and Vapor Sensors? Approaches and Achievements

“…The experiment has shown that the oxidation of PSi is the most effective method for solving problems associated with the instability of PSi properties . It was found that even slightly oxidized PSi may be more stable and may contain fewer interface states affecting Fermi‐level pinning.…”

Impedance Spectroscopy of Hierarchical Porous Nanomaterials Based on por-Si, por-Si Incorporated by Ni and Metal Oxides for Gas Sensors

“…Porous silicon (por-Si) is very promising as a matrix material for gas sensors due to its high surface to volume ratio and reactivity with the environment as well as its hierarchical porous texture with different pore sizes that can be tuned for certain goals and also due to facility of integration with silicon microchips [22][23][24][25][26].…”

“…It was shown that por-Si has a potential use in sensing of organic vapors and ammonia when covered with an oxide layer [22]. Graphene decorated por-Si showed enhanced sensing property to low-ppm H 2 at room temperature in comparison to that of pristine por-Si [23].…”