Low Frequency Noises Of Hydrogen Sensors On The Base Of Silicon Having Nano-Pores Layer

Abstract

Sensors have sandwich stracture metal/porous silicon/crystalhne silicon/Al. The contact metal on porous silicon was from Au and from Pd. Porosity of the samples is 57% and 63%. Low frequency noises before, during and after influence of hydrogen gas flow are studied. Noise spectra of the samples in general have Ij f^ forms with 0.7 < / < 1.

New Applications of the Noise Spectroscopy for Hydrogen Sensors

“…High sensitivity of spectral dependence of noise to carbon monoxide and ethyl alcohol vapors concentration of the sensors made on metal-porous Si-crystalline Si-metal sensors are observed [5]. It also observed the growth of the frequency index γ of the 1/f-noise Hooge formula: 0.5 in air, 0.85 for the air mixed with ethyl alcohol vapors; 1 for the air mixed 0.1% H 2 , and 1.3 for the air mixed with 0.4% CO [5] [10]. For describing noise fluctuation in gas sensors, several models are proposed: a model of adsorption-desorption noise in metal-oxide gas sensors using Langmuir's and Wolkenstein theories [11] [12], "Correlated number-mobility fluctuation model" [10].…”

“…It also observed the growth of the frequency index γ of the 1/f-noise Hooge formula: 0.5 in air, 0.85 for the air mixed with ethyl alcohol vapors; 1 for the air mixed 0.1% H 2 , and 1.3 for the air mixed with 0.4% CO [5] [10]. For describing noise fluctuation in gas sensors, several models are proposed: a model of adsorption-desorption noise in metal-oxide gas sensors using Langmuir's and Wolkenstein theories [11] [12], "Correlated number-mobility fluctuation model" [10]. For the bio-chemical sensors, we also have proposed trapping-detraping (adsorption-desorption) and charge fluctuation models [13] [14].…”

Static and noise characteristics of nanocomposite gas sensors

“…Phenomenon of low frequency (LF) fluctuations of electric current in semiconductors and semiconductor devices is an object of investigations of many researchers and engineers [9][10][11][12][13][14]. Studies have shown that behavior and magnitude of LF-noise in devices based on nanosize porous silicon differs essentially from the noise in devices based on crystalline silicon [10][11][12]. Since the sensors based on porous silicon, are very sensitive to different gases present in environment, the level and frequency dependence of LF-noises in these sensors also depends on the type and concentration of these gases.…”