Temperature-Dependent n–p–n Switching and Highly Selective Room-Temperature n-SnSe₂/p-SnO/n-SnSe Heterojunction-Based NO₂ Gas Sensor

Abstract

Many toxic gases are mixed into the atmosphere because of increased air pollution. An efficient gas sensor is required to detect these poisonous gases with its ultrasensitive ability. We employed the thermal evaporation method to deposit an n-SnSe2/p-SnO/n-SnSe heterojunction and observed a temperature-dependent n–p–n switching NO2 gas sensor with high selectivity working at room temperature (RT). The structural and morphological properties of the material were studied using the characterization techniques such as XRD, SEM, Raman spectroscopy, XPS, and HRTEM, respectively. At RT, the device response was 256% for 5 ppm NO2. The response/recovery times were 34 s/272 s, respectively. The calculated limit of detection (LOD) was ∼115 ppb with a 38% response. The device response was better with NO2 gas than with SO2, NO, H2S, CO, H2, and NH3. The mechanism of temperature-dependent n–p–n switching, fast response, recovery, and selective detection of NO2 at RT has been discussed on the basis of physisorption and charge transfer. Thus, this work will add a new dimension to 2D materials as selective gas detectors at room temperature.

Solution-processed In2Se3 nanosheets for ultrasensitive and highly selective NO2 gas sensors

“…To evaluate the performance for NO 2 sensing, we compared α-In 2 Se 3 with other sensors based on 2D semiconductors (SnS 2 , 65 Sb 2 Se 3 , 66 N-doped In 2 S 3 , 67 black phosphorus, 68 reduced graphene oxide 69 ), graphitic carbon nitride, 70 metal oxides (In 2 O 3 nanoparticles, 71,72 SnO 2 nanowires 73 ), and various heterostructures (SnO 2 /SnSe 1.7 , 74 In 2 O 3 /SnS 2 , 75 SnO 2 /SnS 2 , 76 SnSe 2 /SnO/SnSe, 77 In 2 O 3 nanoparticles/SnO 2 nanowires 73 ). The comparative analysis highlights the superior suitability of α-In 2 Se 3 compared to state-of-the-art materials, with significantly higher sensing response and lower LOD than all other above-mentioned systems.…”

Ultrasensitive and Exclusive Chemiresistors with a ZIF-67-Derived Oxide Cage/Nanofiber Co3O4/In2O3 Heterostructure for Acetone Detection

“…Sensing materials are considered the most crucial component of chemiresistive gas sensors. To date, various chemiresistive gas sensors, including metal oxide semiconductors (MOSs), ,,, metal dichalcogenides, , transition metal carbides or carbonitrides (Mxenes), , and carbonaceous materials, have attracted considerable attention. Among them, MOSs, such as In 2 O 3 , ,, ZnO, ,, SnO 2 , , WO 3 , CeO 2 , , Co 3 O 4 , and CuO, owing to their low cost, fast response time, simple fabrication, excellent stability, and rich active sites, have been widely used for detecting VOCs.…”

Adsorption Behavior of Dissolved Gas Molecules in Transformer Oil on Rh Modified GeSe Monolayer

“…According to the dimension classification, nanoelectronic materials can be divided into low-dimensional structures (zero-dimensional, one-dimensional, two-dimensional) and high-dimensional structures (three-dimensional). − Among them, two-dimensional nanoelectronic materials such as graphene, boron nitride, molybdenum disulfide, and germanium selenide have become a research hotspot in the field of gas sensing due to their large specific surface area, excellent electrical properties, and excellent mechanical properties. − These two-dimensional nanoelectronic materials have strong interactions with the adsorbed gas, making their electrical properties more susceptible to physical or chemical adsorption. Among them, GeSe as a new p-type semiconductor with about 1.0 eV has attracted the attention of researchers in the field of gas sensing. − In addition, GeSe also has the advantages of good stability, abundant reserves, and no pollution to the environment, which can become a large-scale prepared gas sensing material for the future. − However, due to the limitation of physical and chemical properties of intrinsic GeSe, its gas sensing monitoring sensitivity is low, the gas sensing response speed is slow, and the selectivity is poor. To solve the above problems, researchers used a variety of physical and chemical methods, including mechanical deformation, organic functional group modification, and metal modification, to modify its microstructure to improve its gas sensing properties. − Among them, the noble metal doping method can effectively improve the response value and selectivity of gas sensing materials by reducing the reaction energy barrier between gas sensing and the target gas and increasing the percentage of activated molecules.…”