Dresden 2020 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 24: Materials for Sensors and Actuators

MM 24.5: Talk

Tuesday, March 17, 2020, 12:45–13:00, IFW B

Fabrication of ZnO/Si NWs p-n Heterojunction array based High Response Nitric Oxide (NO) Gas Sensor with Noise Limited Detectivity Approaching 10 ppb — •Chandan Samanta, Ankita Ghatak, A K Raychaudhuri, and Barnali Ghosh — S N Bose National Centre for Basic Sciences, Kolkata, India

Gas sensors, particularly those based on solid state devices are commercially available and are widely used to hazardous gas monitoring and new vistas for application are opening up for solid state gas sensors for use in healthcare such as exhaled breath analysis. In this work we report a ZnO/Silicon nanowires (ZnO/Si NWs) based p-n heterojunction diode array based Nitric Oxide (NO) gas sensor that can show a calibrated detection capability at least down to 0.5ppm (with dry N2 as the ambience gas). Utilization of cost effective chemical technique for fabrication of sensor on silicon is compatible with wafer level processing and easily connecting with silicon IC technology. The vertically aligned Si NWs array has been made by electroless etching method and the ZnO nanostructure was made by chemical solution deposition and spin-coating. We observe that the heterostructure leads to a synergetic effect where the sensing response is more than the sum total of the individual components. Extensive cross-sectional electron microscopy and composition analysis by line EDS allowed us to make a physical model. The comparison of the simulation results with the experiment point out the device parameters that enhance the device response.