scholarly journals Adsorption of NO2 and H2S on ZnGa2O4(111) Thin Films: A First-Principles Density Functional Theory Study

2020 ◽  
Vol 10 (24) ◽  
pp. 8822
Author(s):  
Jen-Chuan Tung ◽  
Yi-Hung Chiang ◽  
Ding-Yuan Wang ◽  
Po-Liang Liu
Keyword(s):  
Work Function ◽  
First Principles ◽  
Density Functional ◽  
Total Energy Density ◽  
Energy Density Functional ◽  
Functional Theory ◽  
Function Change ◽  
Work Function Change ◽  
H2s Adsorption ◽  
Maximum Work

We performed first-principles total-energy density functional calculations to study the reactions of NO2 and H2S molecules on Ga–Zn–O-terminated ZnGa2O4(111) surfaces. The adsorption reaction and work functions of eight NO2 and H2S adsorption models were examined. The bonding of the nitrogen atom from a single NO2 molecule to the Ga atom of the Ga–Zn–O-terminated ZnGa2O4(111) surfaces exhibited a maximum work function change of +0.97 eV. The bond joining the sulfur atom from a single H2S molecule and the Ga atom of Ga–Zn–O-terminated ZnGa2O4(111) surfaces exhibited a maximum work function change of −1.66 eV. Both results concur with previously reported experimental observations for ZnGa2O4-based gas sensors.

scholarly journals Influences of Work Function Changes in NO2 and H2S Adsorption on Pd-Doped ZnGa2O4(111) Thin Films: First-Principles Studies

2021 ◽  
Vol 11 (11) ◽  
pp. 5259
Author(s):  
Jen-Chuan Tung ◽  
Ding-Yuan Wang ◽  
Yu-Hsuan Chen ◽  
Po-Liang Liu
Keyword(s):  
Work Function ◽  
First Principles ◽  
First Principle ◽  
Gas Concentration ◽  
Suitable Material ◽  
Gas Detectors ◽  
Function Change ◽  
Work Function Change ◽  
H2s Adsorption ◽  
Maximum Work

The work function variations of NO2 and H2S molecules on Pd-adsorbed ZnGa2O4(111) were calculated using first-principle calculations. For the bonding of a nitrogen atom from a single NO2 molecule to a Pd atom, the maximum work function change was +1.37 eV, and for the bonding of two NO2 molecules to a Pd atom, the maximum work function change was +2.37 eV. For H2S adsorption, the maximum work function change was reduced from −0.90 eV to −1.82 eV for bonding sulfur atoms from a single and two H2S molecules to a Pd atom, respectively. Thus, for both NO2 and H2S, the work function change increased with an increase in gas concentration, showing that Pd-decorated ZnGa2O4(111) is a suitable material in NO2/H2S gas detectors.

The Studies of ScB2 (0001) Surfaces from the First-Principles

2014 ◽  
Vol 989-994 ◽  
pp. 688-693
Author(s):  
Hui Zhao ◽  
Qian Han
Keyword(s):  
Energy Density ◽  
Total Energy ◽  
Electronic Properties ◽  
First Principles ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Surface Structures ◽  
Charge Accumulation ◽  
Total Energy Density ◽  
Energy Density Functional

We conduct first-principles total-energy density functional calculations to study the ScB2 (0001) surfaces. The optimized surface structures and electronic properties are obtained. The results show that Sc-terminated surface is thermodynamically more favorable in most of range. The relaxations indicate that it is mainly localized within top three layers and it is less relaxation for Sc-terminated surface. The surface induced features in DOS disappear slowly for the B-terminated surface but vanish rapidly for the Sc-terminated surface. For the Sc-terminated surface, it shows strong metallic property. Simultaneously, both termination surfaces are found charge accumulation relative to the idea surface. Sc-B bonds are strengthened result in the outermost interface spacing are all contracted.

A first principles study of H2S adsorption and decomposition on a Ge(100) surface

RSC Advances ◽  
2015 ◽  
Vol 5 (5) ◽  
pp. 3825-3832 ◽  
Author(s):  
Tsung-Fan Teng ◽  
Santhanamoorthi Nachimuthu ◽  
Wei-Hsiu Hung ◽  
Jyh-Chiang Jiang
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
First Principles ◽  
Density Functional ◽  
Reaction Paths ◽  
Functional Theory ◽  
First Principles Study ◽  
H2s Adsorption

We employed density functional theory (DFT) calculations to examine the adsorption configurations and possible reaction paths for H2S on a Ge(100) surface.

First-Principle Studies on the Stability of AlN(0001)/NbB2(0001) Interface

2014 ◽  
Vol 1052 ◽  
pp. 18-23
Author(s):  
Hui Zhao ◽  
Kai Yuan Liu ◽  
Qian Han
Keyword(s):  
Density Functional Theory ◽  
Energy Density ◽  
Density Functional ◽  
Stable Configuration ◽  
Stable Model ◽  
First Principle ◽  
Total Energy Density ◽  
Energy Density Functional ◽  
Functional Theory ◽  
The Stability

The stability behaviour of AlN(0001)/NbB2(0001) interface was calculated by first-principle total-energy density functional theory. The calculation indicated that the stable NbB2(0001) surface is B terminated. We joined the AlN(0001) slab and the NbB2(0001) slab with different terminations together to construct all possible AlN(0001)/NbB2(0001) interface models, and calculated their interface energies to confirm the relatively stable model. We concluded that the structure with Al is on top of B in the interface AlN (0001)/NbB2(0001) is the most stable configuration.

A DFT INVESTIGATION OF SULFUR ADSORPTION ON Ir(100)

2007 ◽  
Vol 06 (01) ◽  
pp. 177-185 ◽  
Author(s):  
WUYING HUANG ◽  
WENZHEN LAI ◽  
DAIQIAN XIE
Keyword(s):  
Work Function ◽  
Density Functional ◽  
Generalized Gradient ◽  
Function Change ◽  
Work Function Change ◽  
Bonding Density ◽  
Adsorption Geometry ◽  
A Charge ◽  
Sulfur Adsorption ◽  
Good Agreement

The adsorptions of sulfur atom on the Ir (100) surface at p (2 × 2) and c (2 × 2) phases were investigated by the density functional calculations within the generalized gradient approximation. The adsorption energy, adsorption geometry, work function change, and charge density distribution were analyzed. The hollow site was found to be the most stable, followed by the bridge and the top sites. The calculated adsorption geometries were in good agreement with the observed results. Particularly, it was found that the adsorption of S on Ir (100) caused a work function decrease. A charge accumulation at the interface between the S layer and the Ir substrate, which centered closer to the S atom, suggests a polar covalent bonding. Density of states (DOS) analysis showed that the adsorption of S induces a reduction of the surface Ir d-orbital DOS around the Fermi level.

Work function change of Ni, HfO2 films and Ni/HfO2 interfaces as a function of external electric field

2015 ◽  
Vol 29 (23) ◽  
pp. 1550168 ◽  
Author(s):  
Kehua Zhong ◽  
Guigui Xu ◽  
Jianmin Zhang ◽  
Renyuan Liao ◽  
Zhigao Huang
Keyword(s):  
Electric Field ◽  
Work Function ◽  
External Electric Field ◽  
Density Functional ◽  
Functional Theory ◽  
Effective Work ◽  
Effective Work Function ◽  
Function Change ◽  
Variation Versus ◽  
Work Functions

In this paper, the effects of external electric field on the work functions for Ni(001), Ni(111), HfO2(001) and HfO2(111) films and the effective work functions for Ni(001)/HfO2(001) and Ni(111)/HfO2(111) interfaces were studied by first-principles methods based on density functional theory (DFT). It is found that the work functions for all the systems change linearly with the strength of external electric field. Comparing the slopes of the work function variation versus external electric field strength for Ni, HfO2 films and Ni/HfO2 interfaces, we have found that the response of the effective work function to external electric field for Ni/HfO2 interfaces is determined by the response of the HfO2 side to external electric field.

scholarly journals Intermediate Band Studies of Substitutional V2+, Cr2+, and Mn2+ Defects in ZnTe Alloys

2020 ◽  
Vol 10 (24) ◽  
pp. 8937
Author(s):  
Jen-Chuan Tung ◽  
Bang-Wun Lin ◽  
Po-Liang Liu
Keyword(s):  
Energy Density ◽  
Transition Metal ◽  
First Principles ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Emission Spectra ◽  
Total Energy Density ◽  
Energy Density Functional ◽  
Intermediate Band ◽  
Jahn Teller

We present first-principles total-energy density functional calculations to study the intermediate band states of substitutional V2+, Cr2+, and Mn2+ ions in ZnTe alloys. The intermediate band states of substitutional transition metal defects of TM2+xZn1−xTe (TM = V, Cr, Mn) alloys are examined as their atomic, structural, and electronic analysis. Our findings show that the scissor-corrected transitions due to Jahn-Teller effects lead to the wavelengths 2530 nm and 2695 nm in the emission spectra. Our findings agree with previously reported experimental results.

ADSORPTION OF Li ON Mo(110) SURFACE: A FIRST-PRINCIPLES STUDY

2009 ◽  
Vol 16 (04) ◽  
pp. 589-597 ◽  
Author(s):  
Y. G. ZHOU ◽  
X. T. ZU ◽  
J. L. NIE ◽  
H. Y. XIAO
Keyword(s):  
Work Function ◽  
First Principles ◽  
Density Functional ◽  
Experimental Finding ◽  
Function Analysis ◽  
Density Functional Theory Calculations ◽  
High Coverage ◽  
Functional Theory ◽  
Li Adsorption ◽  
Energy Of Formation

Periodic, self-consistent, density functional theory calculations have been performed to investigate Li adsorption on Mo (110) surface. It turns out that the long-bridge site is the most stable site and the Li – Mo surface alloy forms easily at high coverage with the substitution of Mo by Li atoms in the outermost layer. Work function analysis showed that the work function decreases dramatically as the coverage from 0 to 0.5 ML, and finally increases again at the coverage of 1 ML, which agrees well with the experimental finding of Kroger et al. (Surf. Sci.449 (2000) 227–235). Vibrational properties, diffusion barrier of Li along the Mo (110) surface, and the energy of formation of the surface have also been investigated for Li adsorption at various coverages.

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