New Type Of Porous Silicon Ethanol Gas Sensors

Alcohol is volatile, belonging to the flammable gas and easily exploded in the air. So it is necessary to monitor alcohol concentration in the industry production and road transportation. At present the common used alcohol sensor is fuel cell type and semiconductor type,with weakness being either high price or poor selectivity and demanding the heat device.Therefore it is very significant to develop the sensor of low price, high sensitivity and selectivity,detecting lower alcohol concentration. The main advantages of porous silicon gas sensor are higher sensitivity and selectivity without heating in the room temperature, high measure precision and low price.The main research contents of this paper are as follows. Firstly, a large quantity of literature are consulted, the domestic and international present development of porous silicon gas sensor are studied. Secondly, hydrotheemaiiy etched method is used to prepare porous silicon of special shape and structure.Combining magnetron sputtering technology designs and makes membrane porous silicon sensor,it has good resistance and capacitance response when adsorbs alcohol.In the room temperature the testing system is setted up and firstly studies and deduces the performance of porous silicon alcohol gas sensor.When the surface of porous silicon adsorbs gas molecule, the conductivity and dielectric Constance of porous silicon membrane take place to changes.So that the sensor's resistance and capacitance can vary accordingly. The gas sensing mechanism is deeply researched and brings up equivalent circuit.Moreover the influence of parasitics resistance and capacitance are analyzed. Fartherly, the methods and ways to improve sensor's performance are discussed.The compound membrane of porous silicon/ZnO has been manufactured in the first time.The structure of this compound membrane both reserves the pillar construction benificial to adsorb gas molecule and grows the good sensitivity ZnO material in the surface, so that it enhances the stability , selectivity and temperature characteristic of porous silicon alcohol sensor.With the road transportation examining the driver's quantity of drinking alcoholfor example, it's the very first time to put forward the feasibility of applying porous silicon gas alcohol sensor in practice.Finally, the weakness and advantages of porous silicon gas alcohol sensor are summarized and prospects of potential application of porous silicon are presented.