Nanoheterogeneeous filamentary materials based on semiconducting oxides for chemical sensors

  The present study aims at developing and testing a new generation of sensor materials based on the whiskers of n-type ZnO and SnO2 and immobilized on the surface of oxide clusters p-type CuO, NiO, PdO, to solve the problem of increasing the sensitivity , selectivity and speed sensor materials to toxic and explosive products in the air.

  As a result of 1 - 3 stages of work to obtain new materials not previously studied , representing whiskers SnO2 and ZnO n- type conductivity , which are immobilized on the surface of clusters of CuO (PdO, NiO) p-type conductivity . Such materials have a high specific surface area , high adsorption capacity and the electrical properties depend strongly on the composition of the atmosphere. The presence of pn junctions significantly reduces the flow channel dimensions of the charge carriers in the filaments and gives hope for a high sensitivity to the presence of materials nanoheterogeneeous air gas molecules oxidants or reducing agents.

 Stage 4 works identified sensory parameters nanoheterogeneeous materials with detection of major air pollutants at the level of maximum allowable concentrations : the detection limit , the dependence of the sensor signal from the temperature and concentration of the target gas , the effect of humidity on the sensor signal at a temperature corresponding to the maximum signal . All studies were performed using microelectronic chips. For material n-SnO₂/p-CuO measured sensory properties of whiskers on the unit . For comparison, measured sensory parameters nanocrystalline powders of tin dioxide , the modified catalytic clusters. The optimum compositions nanoheterogeneeous materials to create semiconductor gas sensors resistive type .

KEYWORDS

    Metal oxides, nanocrystalline semiconductors filamentary, solid-gas reactions, electrical conductivity sensors .