Low‐frequency noise in structures with porous silicon in different gas media

Abstract

Noise properties of porous silicon/single-crystalline silicon structures under exposure to active gases are investigated for the first time. Current-voltage and noise characteristics of samples are measured. The Al/porous silicon/single-crystalline Si/Al sandwich-structures were placed in a special chamber and the influence of adsorption of various gases on low-frequency noise of the samples was revealed. The adsorption changes the dynamics of the interaction of charge carriers with traps, i.e. the noise characteristics of the samples. The results are encouraging for practical applications of porous silicon structures as gas sensors using measurements of low-frequency noise characteristics.

Hazardous Gases Detection by Fluctuation-Enhanced Gas Sensing

“…Such DC resistance responses create a problem with gas detection because the same change of DC resistance can be induced by a respectively large amount of NH 3 or a small amount of H 2 S. It is known that gas adsorption processes on porous semiconductor surfaces, such as used in TGS sensors, may result in changing electrical properties of the surface [1,2]. These changes are observed as resistance fluctuations and can be utilized as a source of information for improving the sensitivity and selectivity of gas detection by a single gas sensor [3][4][5][6][7]. Fluctuations usually are analyzed by power spectral density estimation, that means application of the FFT algorithm for low-frequency noise [8,9].…”

Fluctuation-enhanced gas sensing in practice

“…In the case of DC current generator drive, the resistance fluctuations who show up as voltage noise and its power density spectrum can be characteristics of the sensed agent ( Fig. 1) [1][2][3][4][5][6][7]. In nanoparticle films and thin films it can significantly improve the sensitivity, as it was demonstrated in various experiments [5,6].…”

Porous silicon gas sensors

“…We studied experimental samples of PSi-layered structures Au/PSi/ SCS/Al (SCS being single crystal silicon) (Mkhitaryan et al ., 2007a(Mkhitaryan et al ., , 2007b. The PSi layer was formed by electrochemical etching on a substrate made of heavily doped p +-type silicon with orientation (100) and resistivity of 0.01 Ω cm.…”