Cadmium compounds with one dimension (1D) nanostructures have attracted attention for their excellent electrical and optical properties. In this study, vertically aligned CdTe-Si nanostructures with high density were synthesized by several simple chemical reactions. First, l D Te nanostructures were synthesized by silver assisted chemical Si wafer etching followed by a galvanic displacement reaction of the etched Si nanowires. Nanowire length was controlled from 1 to 25 μm by adjusting etching time. The Si nanowire galvanic displacement reaction in HTeO₂ + electrolyte created hybrid 1D Te-branched Si nanostructures. The sequential topochemical reaction resulted in Ag₂Te-Si nanostructures, and the cation exchange reaction with the hybrid 1D Te-branched Si nanostructures resulted in CdTe-Si nanostructures. Wet chemical processes including metal assisted etching, galvanic displacement, topochemical and cation exchange reactions are proposed as simple routes to fabricate large scale, vertically aligned CdTe-Si hybrid nanostructures with high density.

In this work, one dimension In₂O₃ nanostructures as detecting materials for indoor toxic gases were synthesized by an electrospinning process. The morphology of electrospun In₂O₃ nanofibers was controlled by electrolyte composition, applied voltage and working distance between a nozzle and a substrate. The synthesized In₂O₃ nanofibers-based paste with/without carbon black additives was prepared for the integration on a sensor device. The integration of In₂O₃ sensing materials was conducted by a hand-printing of the paste into the interdigit Au electrodes patterned on Si wafer. Gas sensing properties on CO and HCHO gases were characterized at 300℃. The evaluated sensing properties such as sensitivity, response time and recovery time were improved in In₂O₃ nanofiber pastes with carbon black, compared to the paste without carbon black.