Gas sensitive porous silicon sensor using rapid thermal annealing screen printing contacts

Abstract

The development of sensitive porous silicon (PS) gas sensor which utilizes screen printing for the front and back contacts metallization has been reported. Application of the thick-film technology results in highly reproducible and economic fabrication of the contacts. We present the design, fabrication, characterization and results when devices were submitted to different gases as opposed to a controlled environment such as vacuum. The C-V and I-V measurements performed on metal/CH x /porous silicon/silicon structure showed that the electrical properties of the device are extraordinary sensitive to various gases, oxygen, propane, carbon dioxide at disproportionate level. The response of this device, which operates at bias voltages of 10 -100 mV, is rapid and reversible. The electrically operated sensor is more sensitive to oxygen and shows an opposite behaviour if exposed to a reducing environment.