We report the fabrication of a highly sensitive gas sensor based on a network of nanostructured TiO2 hollow hemispheres (NTHH). O 2 plasma etching induces cross-linking of hexagonal-close-packed polystyrene array, which is adopted as a template substrate for room-temperature deposition of TiO2 thin film. High-temperature calcination effectively removes polystyrene template beads and promotes crystallization of TiO2, finally producing cross-linked NTHH via nanobridges. The gas-sensing capability of a NTHH-based sensor is demonstrated using 1-500 ppm CO. Our sensor exhibits a very high response of 4220% change in resistance when exposed to 500 ppm CO at 250 °C, whereas a gas sensor based on a plain TiO2 film shows a 195% change. The high sensitivity of the NTHH-based sensor is attributed to the enhanced gas sensing performance of the narrow nanobridges between hollow hemispheres.
Bibliographical noteFunding Information:
The authors thank Beom-Keun Yoo and Min-Gyu Kang for SEM measurements. This work was financially supported by the Core Technology of Materials Research and Development Program of the Korea Ministry of Intelligence and Economy (No. K0004114).
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Metals and Alloys
- Electrical and Electronic Engineering
- Materials Chemistry