UV Enhanced NO₂Sensing Properties of Pt Functionalized Ga₂O₃Nanorods

Abstract

Ga2O3 one-dimensional (1D) nanostructures were synthesized by using a thermal evaporation technique. The morphology, crystal structure, and sensing properties of the Ga2O3 nanostructures functionalized with Pt to NO2 gas at room temperature under UV irradiation were examined. The diameters of the 1D nanostructures ranged from a few tens to a few hundreds of nanometers and the lengths ranged up to a few hundreds of micrometers. Pt nanoparticles with diameters of a few tens of nanometers were distributed around a Ga2O3 nanorod. The responses of the nanorods gas sensors fabricated from multiple networked Ga2O3 nanorods were improved 3-4 fold at NO2 concentrations ranging from 1 to 5 ppm by Pt functionalization. The Pt-functionalized Ga2O3 nanorod gas sensors showed a remarkably enhanced response at room temperature under ultraviolet (UV) light illumination. In addition, the mechanisms via which the gas sensing properties of Ga2O3 nanorods are enhanced by Pt functionalization and UV irradiation are discussed.

Monolithic Micro Light-Emitting Diode/Metal Oxide Nanowire Gas Sensor with Microwatt-Level Power Consumption

“…The short-term recommended exposure limit of NO 2 is 1 ppm by National Institution for Occupational Safety and Health (NIOSH) guidelines . The NO 2 sensing mechanism promoted by UV photoactivation can be explained by the following reactions where e ( h ν) – is the photoelectron generated by UV irradiation. − These reaction mechanisms indicate that photoelectrons promote the adsorption of ionized oxygen species (O 2(ad) – or the form of O – /O 2– by the spontaneous transition) and dissociation of NO 2 molecules at the surface of metal oxides. Because of surface depletion by electron transfer from metal oxides to surface oxygen, the resistance of n-type ZnO increases under NO 2 exposure.…”