Gas Sensing Properties of Nanocrystalline Silicon Carbide Films: Experimental Results | Chapter 02 | Innovations in Science and Technology Vol. 5

 The impact of the air environment on the electrical conductivity of nanocrystalline thin SiC films formed on sapphire by direct ion deposition was studied. Gas sensitivity studies were performed on two series of nc-SiC films with distinct structures: the first series was monopolytypic and comprised mostly 3C-SiC polytype nanocrystals, while the second series was a nanoheterostructure including a mix of 3C-SiC and 21R-SiC nanocrystals. The films developed gas sensitivity after annealing in vacuum at temperatures exceeding 500 K. At 700 K, tests of the films' gas sensitivity to the air atmosphere revealed that the monopolytype film's resistance increased 12 times and the heteropolytype film's resistance increased approximately 16 times.

The goal of this study was to evaluate the effect of the air atmosphere on the electrical conductivity of thin nanocrystalline SiC films with distinct polytype structures at different temperatures.

Author(S) Details

A. V. Semenov
National Technical University “Kharkiv Polytechnic Institute”, Kharkiv, 2, Kyrpychova Str., 61002, Ukraine.

A. A. Kozlovskyi
Institute for Single Crystals NAS of Ukraine, Nauky Ave. 60, Kharkiv, 61001, Ukraine.

S. N. Skorik
Institute for Single Crystals NAS of Ukraine, Nauky Ave. 60, Kharkiv, 61001, Ukraine.

D. V. Lubov
National Technical University “Kharkiv Polytechnic Institute”, Kharkiv, 2, Kyrpychova Str., 61002, Ukraine.

View Book:- https://stm.bookpi.org/IST-V5/article/view/5697

The Chemresistive Properties of SiC Nanocrystalline Films with Different Conductivity Type: Experimental Results | Chapter 08 | Innovations in Science and Technology Vol. 4

 Thin nanocrystalline SiC sheets with various forms of conductivity have been shown to be capable of detecting oxidative (O2) and reducing gases (CO, CH4) at maximum permissible quantities for human safety. It was discovered that n-nc-SiC films with electronic conductivity had a higher gas sensitivity Sn to the action of gases over a wide concentration range than p-nc-SiC films with hole conductivity sensivity Sp. The sensitivity ratio of the films Sn / Sp was 2.9, 4.8, and 10 for the highest allowed concentrations of O2 (3%), CO (0.1%), and CH4 (10%), respectively. We used a basic resistor shape optimization technique for study, which allowed us to greatly boost the sensitivity of films to gases, allowing us to detect extremely low gas concentrations. As a result, high-temperature gas sensors based on nc-SiC films can detect reactive gases in a wide range of concentrations, including threshold allowed values.

Author(S) Details

A. V. Semenov
National Technical University “Kharkiv Polytechnic Institute” 2, Kyrpychova Str., Kharkiv, 61002, Ukraine.

D. V. Lubov
National Technical University “Kharkiv Polytechnic Institute” 2, Kyrpychova Str., Kharkiv, 61002, Ukraine.

A. A. Kozlovskyi
Institute for Single Crystals NAS of Ukraine, Nauky Ave. 60, Kharkiv, 61001, Ukraine.

View Book:- https://stm.bookpi.org/IST-V4/article/view/5561