Single ZnO Nanowire for Electrical and Optical NO2 Gas Sensing: Origin of Reversible and Irreversible Gas Effects Investigated by Photoluminescence Spectroscopy

Year: 2024

Authors: Rigoni F., Zappa D., Baratto C., Faglia G., Comini E.

Autors Affiliation: Univ Brescia, Dept Informat Engn, Sensor Lab, I-25133 Brescia, Italy; CNR INO Brescia, I-25123 Brescia, Italy.

Abstract: In this work, the gas sensing properties of a single ZnO nanowire (NW) are investigated, simultaneously in terms of photoluminescence (PL) and photocurrent (PC) response to NO2 gas, with the purpose of giving new insights on the gas sensing mechanism of a single 1D ZnO nanostructure. A single ZnO NW sensing device was fabricated, characterized, and compared with a sample made of bundles of ZnO NWs. UV near-band-edge PL emission spectroscopy was carried out at room temperature and by lowering the temperature down to 77 K, which allows detection of resolved PL peaks related to different excitonic transition regions. Surface effects were observed in PL maps, considering different nano and microstructures. Electrical and optical measurements were acquired at the same time during the NO2 gas exposure, allowing for the comparison of PL and PC response times and signal recovery. During NO2 gas desorption, irreversible behavior in the surface-related and donor-acceptor pair (DAP) regions is interpreted as the effect of an initial transient when electronic transfer from the gas molecules to the bulk occurs through the ZnO NW surface which acts as a channel. To the best of our knowledge, this is the first work which investigates the simultaneous PL optical and PC electrical response signals of a single ZnO NW to gas exposure.

Journal/Review: ACS SENSORS

Volume: 9 (9)      Pages from: 4646  to: 4654

More Information: The authors want to acknowledge Maurizio Donarelli for the realization of single nanowire device by EBL. F.R. wants to thank Beryl Frishtick for the editing and language revision.
KeyWords: ZnO single nanowire; NW; opticalgas sensing; NO2; photoluminescence gassensing
DOI: 10.1021/acssensors.4c00901