Top-Down Approaches for 10 nm-Scale Nanochannel: Toward Exceptional HS Detection.

Metal oxide semiconductors (MOS) have proven to be most powerful sensing materials to detect hydrogen sulfide (HS), achieving part per billion (ppb) level sensitivity and selectivity. However, there has not been a way of extending this approach to the top-down HS sensor fabrication process, completely limiting their commercial-level productions. In this study, we developed a top-down lithographic process of a 10 nm-scale SnO nanochannel for HS sensor production. Due to high-resolution (15 nm thickness) and high aspect ratio (>20) structures, the nanochannel exhibited highly sensitive HS detection performances (/ = 116.62, τ = 31 s at 0.5 ppm) with selectivity (/ = 23 against 5 ppm acetone). In addition, we demonstrated that the nanochannel could be efficiently sensitized with the p-n heterojunction without any postmodification or an additional process during one-step lithography. As an example, we demonstrated that the HS sensor performance can be drastically enhanced with the NiO nanoheterojunction (/ = 166.2, τ = 21 s at 0.5 ppm), showing the highest range of sensitivity demonstrated to date for state-of-the-art HS sensors. These results in total constitute a high-throughput fabrication platform to commercialize the HS sensor that can accelerate the development time and interface in real-life situations.