Parallel three-dimensional (3D) growth of different nanomaterials with submicrometer resolution is a promising approach to overcome some technological and economic limits encountered in planar integrated homogeneous films. The programmable multimaterial gas phase nanoparticle electrodeposition concept enables the fabrication of a 3D multimodal conductometric gas sensor array. The approach requires the deposition of more than one nanomaterial to achieve orthogonal sensing capabilities and multigas sensitivity and selectivity. The demonstrated "electronic nose"-like array contains 1080 self-aligning 3D nanobridge-based electrical connections of platinum, nickel oxide, and gold on a single chip. The nanobridges form through a nearest neighbor Coulombic interaction. Each gas sensitive bridge is a 3D structure composed of a porous but electrically conducting nanoparticle network. It was found that this architecture is unique, because it does not require external heating to operate. A trimodal sensor array will be demonstrated to detect various levels of ammonia (NH3), carbon monoxide (CO), and hydrogen sulfide (H2S). A 3 × 3 transfer matrix will be discussed to correlate the recorded signals with the gas composition.
Keywords: combinatorial nanofabrication; gas sensing; inorganic nanomaterials; interfacial studies; nanosensors; surface patterning; surface science.