Ultra Violet Irradiation of Metal Oxide Semiconductor Gas Sensors

Abstract

Metal oxide semiconductor gas sensors are widely used for a variety of applications from pollution monitoring to medical breath analysis. One disadvantage for the use of such sensors is the relatively large power requirement that originates from the need to heat the semiconductor material in order to produce a measurable baseline resistance. The use of ultra violet light emitting diodes has been suggested as an alternative way of promoting charge carriers from the materials valence band into the conduction band. In this paper we examine the use of 360 nm ultra violet light emitting diodes as a way of activating a variety of metal oxide thick film sensors. The sensors were evaluated under a variety of irradiation and heating conditions against varying concentrations of ethanol gas. It was found that the optimum operating temperature of the thick film sensors could be dramatically reduced using this approach.