Top-Down Approaches for 10 nm-Scale Nanochannel: Toward Exceptional H₂S Detection

Abstract

Metal oxide semiconductors (MOS) have proven to be most powerful sensing materials to detect hydrogen sulfide (H 2 S), achieving part per billion (ppb) level sensitivity and selectivity. However, there has not been a way of extending this approach to the top-down H 2 S 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 2 nanochannel for H 2 S sensor production. Due to high-resolution (15 nm thickness) and high aspect ratio (>20) structures, the nanochannel exhibited highly sensitive H 2 S detection performances (R a /R g = 116.62, τ res = 31 s at 0.5 ppm) with selectivity (R Hd 2 S /R acetone = 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 H 2 S sensor performance can be drastically enhanced with the NiO nanoheterojunction (R a /R g = 166.2, τ res = 21 s at 0.5 ppm), showing the highest range of sensitivity demonstrated to date for state-of-the-art H 2 S sensors. These results in total constitute a high-throughput fabrication platform to commercialize the H 2 S sensor that can accelerate the development time and interface in real-life situations.

In situ fabrication of a NiO nanoparticles/single-layered MXene nanosheet Schottky heterojunction toward sensing xylene and formaldehyde

“…Kang et al demonstrated that the H 2 S sensor performance can be drastically enhanced with the NiO nanoheterojunction ( R a / R g = 166.2, τ res = 21 s at 0.5 ppm). 17 Zhu et al prepared a kind of 3.9% Ag@UG-NiO sensor whose response to 100 ppm butanone was about 3.1 times higher than that of pure porous spherical NiO. 18 Currently, according to literature reports, researchers have improved the response value and recovery speed of sensors by constructing heterostructures, 19 metal ion doping, 20 regulating the micromorphology 16 and light irradiation.…”

An unexpected interfacial Mo-rich phase in 2D molybdenum disulfide and 3D gold heterojunctions

“…[17][18][19] Direct growth of 2D-TMDs on 3D structured metallic substrates via the CVD method holds promise for the fabrication of high-performance contact interfaces in the 3D integration technology field. [20][21][22][23] Such a chemical reaction process, occurring on the surface of 3D-metals, often allows chemical interaction with the surrounding vapor phase environment that induces the formation of a second phase suitable for multifunctional applications. [24][25][26][27] For instance, a highly ordered 1D intermediate crystal was observed between the MoO 2 substrate and the product 2D MoS 2 obtained through thermal sulfidation, and the subsequent thickening of MoS 2 caused a transition from a p-type to an n-type Schottky contact.…”

Highly Sensitive and Selective Acetylene CuO/ZnO Heterostructure Sensors through Electrospinning at Lean O2 Concentration for Transformer Diagnosis

“…Then, the target molecule reacts with the oxygen ion species on the surface, causing a change in the EDL or HAL, resulting in sensitive detection even at very low concentrations. The main advantages of MOS sensors are low cost, sensitive detection at very low concentrations, facile operation, small size, and facile integration into an integrated circuit (IC). − …”