Ab Initio Studies of Work Function Changes of CO Adsorption on Clean and Pd-Doped ZnGa2O4(111) Surfaces for Gas Sensors

Tung, Jen-Chuan; Huang, Shih-Wei; Pai, Che-An; Horng, Ray−Hua; Chang, Cheng-Chung; Hung, Dun-Ru; Liu, Po−Liang

doi:10.3390/app12125978

Cited by 7 publications

(5 citation statements)

References 22 publications

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“…Furthermore, the energies of the vacuum level and Fermi level, work function, and work function change in our geometric models are shown in Table1. In our previous studies[37][38][39], the alterations in the work function of CO, NO 2 , and H 2 S molecules upon interaction with the ZnGa 2 O 4 (111) surface align with experimental findings. These changes in the work function signify the overcoming of electron barriers induced by gas adsorption, contributing to the quantitative assessment of gas-sensing characteristics in zinc gallium oxide.…”

supporting

confidence: 82%

“…Since InAlN is an n -type semiconductor and acetone gas is a reducing gas, a reduction in depletion width layers is favorable upon exposure to reducing gas. In recent studies, we have successfully illustrated the electron flow from the reducing gas to the n -type semiconductor until the Fermi level equilibrium is achieved [ 37 , 38 , 39 ]. This phenomenon leads to the formation of ohmic contact.…”

Section: Resultsmentioning

confidence: 99%

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Growth and Characterization of Sputtered InAlN Nanorods on Sapphire Substrates for Acetone Gas Sensing

Horng,

Cho,

Chang

et al. 2023

Nanomaterials

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The demand for highly sensitive and selective gas sensors has been steadily increasing, driven by applications in various fields such as environmental monitoring, healthcare, and industrial safety. In this context, ternary alloy indium aluminum nitride (InAlN) semiconductors have emerged as a promising material for gas sensing due to their unique properties and tunable material characteristics. This work focuses on the fabrication and characterization of InAlN nanorods grown on sapphire substrates using an ultra-high vacuum magnetron sputter epitaxy with precise control over indium composition and explores their potential for acetone-gas-sensing applications. Various characterization techniques, including XRD, SEM, and TEM, demonstrate the structural and morphological insights of InAlN nanorods, making them suitable for gas-sensing applications. To evaluate the gas-sensing performance of the InAlN nanorods, acetone was chosen as a target analyte due to its relevance in medical diagnostics and industrial processes. The results reveal that the InAlN nanorods exhibit a remarkable sensor response of 2.33% at 600 ppm acetone gas concentration at an operating temperature of 350 °C, with a rapid response time of 18 s. Their high sensor response and rapid response make InAlN a viable candidate for use in medical diagnostics, industrial safety, and environmental monitoring.

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supporting

confidence: 82%

Section: Resultsmentioning

confidence: 99%

Growth and Characterization of Sputtered InAlN Nanorods on Sapphire Substrates for Acetone Gas Sensing

Horng,

Cho,

Chang

et al. 2023

Nanomaterials

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“…The electron can flow from the sheet to the oxidizing-type gas until equilibrium is reached at the Fermi level, causing alteration to the surface energy band, thus increasing the surface resistance and ϕ. On the other hand, for reducing gases, the electron transfer occurs from the gas molecules to the sheet until the Fermi level is balanced, which results in ohmic contact formation . The ohmic contact makes the electrons inside the sheet easily migrate to the surface, thereby reducing the surface resistance and the ϕ of the adsorbed system.…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, for reducing gases, the electron transfer occurs from the gas molecules to the sheet until the Fermi level is balanced, which results in ohmic contact formation. 56 The ohmic contact makes the electrons inside the sheet easily migrate to the surface, thereby reducing the surface resistance and the ϕ of the adsorbed system. In our case, Bader charge analysis revealed that the charge transfer occurs mostly from Mo 2 CT x to the CWAs.…”

Section: Electrostatic Potential and Work Functionmentioning

confidence: 99%

Molybdenum Carbide MXenes as Efficient Nanosensors toward Selected Chemical Warfare Agents

Panigrahi

Pal

Kaewmaraya

et al. 2023

ACS Appl. Nano Mater.

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There has been budding demand for the fast, reliable, inexpensive, non-invasive, sensitive, and compact sensors with low power consumption in various fields, such as defense, chemical sensing, healthcare, and safe environmental monitoring units. Particularly, efficient detection of chemical warfare agents (CWAs) is of great importance for human safety and security. Inspired by this, we explored molybdenum carbide MXenes (Mo2CT x ; T x = O, F, and S) as efficient sensors toward selected CWAs, such as arsine (AsH3), mustard gas (C4H8Cl2S), cyanogen chloride (NCCl), and phosgene (COCl2) both in aqueous and non-aqueous media. Our calculations based on van der Waals-corrected density functional theory (DFT) revealed that the CWAs bind with Mo2CF2, and Mo2CS2 monolayers under strong chemisorption with binding energies in the range of −2.33 to −4.05 eV, whereas Mo2CO2 resulted in comparatively weak bindings of −0.29 to −0.58 eV. We further reported the variations in the electronic properties, electrostatic potentials, and work functions of Mo2CT x upon the adsorption of CWAs, which authenticated an efficient sensing mechanism toward CWA detection. Statistical thermodynamic analysis was applied to explore the sensing properties of Mo2CT x at various temperatures and pressures. These findings will pave the way to an innovative class of low-cost reusable sensors for the sensitive and selective detection of highly toxic CWAs in air as well as in aqueous media.

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“…There are many published works on the ab initio studies of adsorption of CO on W(111) and Pt(111), starting with the work if Chen, Scholl and Johnson [1] in 2006 to publications in 2022 by Goonusooria [2] and J. C Tung et al [3].…”

Section: Introductionmentioning

confidence: 99%

Convergence Issues Associated with Cutoff Energies and Ab Initio Studies of Adsorption of CO on W and Pt

Hanagud,

Zaharieva

2024

MSCE

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The experimental research programs of 1950s, to understand the adsorption of CO on W surfaces, changed to ab initio studies in 2000s. The goals were to seek improved practical applications. Most of the studies were based on density functional theory. Many studies also used programs, such as VASP (Vienna Abinitio simulation package) and CPMD. The computational procedures used plane wave approximations. This needed studies with selection of K points and cutoff energy selection to assure convergence in energy calculations. Observations and analysis of papers published from 2006 to 2022 indicate that the cutoff energies were selected arbitrarily without any needed convergence studies. By selecting a published 2006 paper, this paper has clearly showed that an arbitrary selection of cutoff energy, such as 460 eV, is not in the range of, cutoff energies that assure convergence of energy calculations, with ab initio methods and have indicated correction procedures.

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Ab Initio Studies of Work Function Changes of CO Adsorption on Clean and Pd-Doped ZnGa2O4(111) Surfaces for Gas Sensors

Cited by 7 publications

References 22 publications

Growth and Characterization of Sputtered InAlN Nanorods on Sapphire Substrates for Acetone Gas Sensing

Growth and Characterization of Sputtered InAlN Nanorods on Sapphire Substrates for Acetone Gas Sensing

Molybdenum Carbide MXenes as Efficient Nanosensors toward Selected Chemical Warfare Agents

Convergence Issues Associated with Cutoff Energies and Ab Initio Studies of Adsorption of CO on W and Pt

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