Preparation and characterization Co3O4 nanoparticles on porous silicon for humidity sensor by photoluminescence.

Abstract Porous silicon (PS) has attracted considerable attention as potential materials for gas/vapor sensing because of very high surface to volume ratio. PS with some metals such as Co 3 O 4 is necessary to create and provide new nanocomposite materials with new properties that combine semiconducting and magnetic properties. In the present work, the samples to be studied were characterized from atomic force microscope (AFM), X-ray diffraction (XRD), reflectivity, photoluminescence (PL) spectra and humidity sensor. X-ray diffraction for PS in the range of 20°-70° at 2 theta, show an important peak at 28.35◦ oriented (111), while the Co 3 O 4 /PS have four characteristic peaks at 36.758°, 44.738°, 59.177° and 64.980°, were corresponding to the oriented (311), (222), (511) and (440) respectively. PL test for PS/Co 3 O 4 shows a slightly less intensity and slight change in location in case of PS due to Co 3 O 4 NPs granular size which acts as a cover, thus reducing the surface area of the PS which reduces PL. In PS/Co 3 O 4 sample shows that the PL spectra peak is different from PS at shape and the effect of relative humidity (RH) at this peak due to the decrease of intensity at peak. Through these results we conclude that PS/Co 3 O 4 can be used as sensor humidity. [ABSTRACT FROM AUTHOR]