SnO₂ Nanobelts as a Chemiresistive Platform for an On-Chip Multisensory “Spectrometer” to Selectively Gauge Ions of Inert Gases

The detection of inert gases presents a challenging task because these molecules do not react with most known sensor-based units aimed at environment monitoring. Here, we ionize these molecules in a low-potential discharge mode to force their interaction with semiconducting SnO 2 single-crystal nanobelts (NBs) deposited as a mat over a multielectrode chip and show the ion-induced resistivity changes similar to a conventional operation of the metal oxide sensor. In particular, the conductance of the percolating NB mats is significantly enhanced under irradiation with He +, Ne +, and Ar + ions at a low-pressure oxygen background. The phenomenon is well explained via ab initio calculations performed in the framework of density functional theory (DFT), which clarify the interaction of various ions with SnO 2 nanocrystals related primarily to the appearance of electronic states and redistribution of their density dependent on the kind of ions. The differences in ion interaction with the SnO 2 surface is the background for options to distinguish the inert gases with a SnO 2 NB-based multisensor array as a low-cost selective detector via transferring the variations in a charge exchange at the adsorbate/adsorbent interface into a varied chemiresistive vector signal like a (mass) spectrometer performs.