The indium oxide micro and nanopyramids: Morphology materializing and H2S sensing properties

Abstract

Indium oxide ( In 2 O 3) pyramidal nano and microstructures were prepared by a thermal evaporation and condensation method. The preannealing step affected the nanostructures morphologies and their sensing capability. The nanosize structures have been fabricated in nucleated preorganized situation. By changing from prepared sites to undesired sites, the morphology was deteriorated. The synthesized In 2 O 3 structures were characterized by field emission scanning electron microscopy (FESEM) and the X-ray diffraction (XRD) measurements. The FESEM images showed that nanostructures with 100–250 nm in size were fabricated. The XRD patterns indicated that most of the samples are crystalline. Then, the fabricated structures were investigated for H 2 S gas sensing. The nanocrystal pyramids were found to be sensitive to as low as 100 ppb of H 2 S gas at room temperature and microcrystal ones to 300 ppb. The nanopyramids demonstrated that they were very sensitive to gas presence and their response and recovery time were in a few seconds.