Ammonia sensitivity of amorphous carbon film/silicon heterojunctions

The amorphous carbon film/n-Si (a-C/Si) junctions have been fabricated by magnetron sputtering. The results show that these junctions have good rectifying properties and high ammonia (NH3) gas sensitivity. For a given reverse bias voltage, the resistance of the junction can increase by 100 times rapidly when exposed to NH3 gas. This phenomenon may be attributed to the change of the space charge width of the junction, which is caused by the adsorption of NH3 gas molecules. This study shows that these a-C/Si junctions have potential application as NH3 gas detect sensors. (c) 2007 American Institute of Physics.