Comparative Analysis of InAs Adjacent Nanowire Sensors for Humidity and NO2 Detection

In this work, we selected two nearby individual wurtzite InAs nanowires with electrical contacts at both ends, to exploit paired nanostructures as building blocks for conductometric sensors. The NWs have an average length of 4 μm +/- 250 nm and an average diameter of 60 nm +/- 8 nm and were drop-casted on onto a p++Si/SiO2 substrate, while electrical contacts were realized by e-beam techniques. InAs is well known for the strong presence of surface states, that makes this material very promising for sensing the outside ambient. Gases can be absorbed as charged molecules and this created a strong coupling especially in semiconducting nanowires, which in case of this material can lead to sensing at room temperature of humidity and pollutant gases [1]. Previous studies indicated the need to analyze two nominally identical nanowires in very close configuration to evaluate the effect of proximity on the signal to noise ratio. The functional characterization was carried out in synthetic air to evaluate the potential of sensor prototypes operating in conditions potentially relevant for real-life applications. The comparison of adjacent nanowires can provide further insights on the fundamental interaction mechanisms with humidity and NO2 molecules.