Abstract
The influence of the air atmosphere on the electrical conductivity of nanocrystalline thin SiC films obtained by method of direct ion deposition on sapphire was studied. Measurements were performed on two series of nc-SiC films with different structure: one series contained mainly 3C-SiC polytype nanocrystals and were denoted as monopolytypic, the second series were a nanoheterostructures based on a mixture of 3C-SiC and 21R-SiC nanocrystals. Gas sensitivity of the films appeared after annealing in vacuum at temperatures above 500 K. Measurements of the gas sensitivity of the films to the air atmosphere at a temperature of 700 K showed that the resistance increased for 12 times for the monopolytype film, while the heteropolytype film showed an increase of resistance for almost 16 times.
Highlights
It was found that nanocrystalline SiC (nc-SiC) films containing a single predominant polytype show the thermoactivation conductivity mechanism, and the films containing a mixture of polytypes demonstrate two-channel conductivity mechanism, one of which is based on the tunneling of electrons through the barrier between nanocrystals of different polytypes [8]
One series of films contained mainly 3C-SiC-polytype nanocrystals and was denoted as monopolytypic one (MP-nc-SiC), the second series were nanoheterostructures based on a mixture of 3C-SiC and 21R-SiC nanocrystals (HP-nc-SiC) [12]
The influence of the air atmosphere on the electrical conductivity of nanocrystalline thin SiC films obtained by method of direct ion deposition on sapphire was studied
Summary
In modern developments of semiconductor sensors for detecting and determining of the concentration of gases and gas impurities in the air, layers of metal oxides with an electronic type of conductivity (SnO2, In2O3, ZnO, Fe2O3, CuO, TiO2, etc.) are widely used as gas-sensitive sensors [1, 2]. One of the promising materials with chemical inertness, resistance to radiation impacts and time stability of properties are materials based on SiC [3], in particular, Previously, it was found that nc-SiC films containing a single predominant polytype (monopolytype) show the thermoactivation conductivity mechanism, and the films containing a mixture of polytypes (heteropolytype) demonstrate two-channel conductivity mechanism, one of which is based on the tunneling of electrons through the barrier between nanocrystals of different polytypes [8]. Radiation resistance of such films was studied by us earlier [9]. The gas sensitivity of thin films of nanocrystalline SiC has not been studied
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
