Adsorption of alkali-metal atoms on GaN nanowires photocathode

Cui, Zhen; Li, Enling; Ke, Xizheng; Zhao, Taifei; Yang, Yue; Ding, Yingchun; Liu, Tong; Yao, Qin; Xu, Shan

doi:10.1016/j.apsusc.2017.06.233

Cited by 58 publications

(20 citation statements)

References 33 publications

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“…All the E ads of different sites are negative, which demonstrates that the procedure of alkali-metal adsorption on g-GaN is exothermic and all the adsorption systems are stable. These results are similar to those obtained for alkali-metal-adsorbed GaN nanowires [ 12 ]. Moreover, the calculated results indicate that the most stable position is the T M site; thus, the following discussions only concern the T M adsorption site.…”

Section: Resultssupporting

confidence: 90%

“…The adsorption energy for the alkali-metal-adsorbed g-GaN systems was calculated using the method of Cui et al [ 12 ] According to the following equation: where E ads is the adsorption energy, E g-GaN and E g-GaN:X denote the total energy of pristine g-GaN before and after alkali-metal adsorption, respectively, and μ X is the chemical potential of a single alkali-metal atom. Based on this equation, a negative value of E ads denotes a stable structure.…”

Section: Methodsmentioning

confidence: 99%

“…Atoms adsorbed onto a solid surface can interact indirectly through electron scattering or elastic distortion of the substrate, with the long-range atomic interaction modulated by the substrate playing an important role in atomic self-assembly. Because alkali-metal atoms can easily lose electrons, the adsorption of alkali metals onto semiconductor materials can change them to n-type, which will in turn reduce their work function and change their optoelectronic properties [ 12 ]. In recent years, many research groups have reported studies of the optoelectronic properties of alkali-metal-adsorbed 2D materials [ 13 – 23 ].…”

Section: Introductionmentioning

confidence: 99%

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Alkali-metal-adsorbed g-GaN monolayer: ultralow work functions and optical properties

Cui

Wang

et al. 2018

Nanoscale Res Lett

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The electronic and optical properties of alkali-metal-adsorbed graphene-like gallium nitride (g-GaN) have been investigated using density functional theory. The results denote that alkali-metal-adsorbed g-GaN systems are stable compounds, with the most stable adsorption site being the center of the hexagonal ring. In addition, because of charge transfer from the alkali-metal atom to the host, the g-GaN layer shows clear n-type doping behavior. The adsorption of alkali metal atoms on g-GaN occurs via chemisorption. More importantly, the work function of g-GaN is substantially reduced following the adsorption of alkali-metal atoms. Specifically, the Cs-adsorbed g-GaN system shows an ultralow work function of 0.84 eV, which has great potential application in field-emission devices. In addition, the alkali-metal adsorption can lead to an increase in the static dielectric constant and extend the absorption spectrum of g-GaN.

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Section: Resultssupporting

confidence: 90%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Alkali-metal-adsorbed g-GaN monolayer: ultralow work functions and optical properties

Cui

Wang

et al. 2018

Nanoscale Res Lett

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“…First‐principles calculations were performed using the Vienna ab initio simulation package (VASP), which is based on the density functional theory (DFT) in a plane‐wave basis set with the projector‐augmented wave method. The exchange correlation functional was approximated by the generalized gradient approximation of Perdew, Burke, and Ernzerhof (GGA‐PBE) .…”

Section: Details Of the Calculation Methodsmentioning

confidence: 99%

Effect on Schottky Barrier of Graphene/WS₂ Heterostructure With Vertical Electric Field and Biaxial Strain

Zheng

et al. 2019

Physica Status Solidi (b)

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Graphene has been widely used in many applications, such as sensors, fieldeffect transistors, and integrated circuits due to its high strength and excellent electrical and thermal conductivity. Its lack of a band gap, however, means that applications in some fields are limited. In this paper, using first principles calculations based on the density functional theory method, the electronic properties of graphene/WS 2 heterostructures under electric field and in-plane biaxial strain are investigated. It is found that the two materials are subject to weak van der Waals forces after stacking. The band gap of WS 2 in the graphene/WS 2 heterostructure is reduced by 0.57 eV compared to the intrinsic WS 2 band gap. An n-type Schottky contact with a barrier height of 0.22 eV is formed. In addition, an n-type to p-type Schottky contact transition can be achieved by increasing the applied vertical electric field on the graphene/WS 2 heterostructure. The variation of the barrier heights ϕ Bn and ϕ Bp of the graphene/WS 2 heterojunction with strain is sensitive. However, plane strain can only change the height of the Schottky barrier; the Schottky contact cannot change from n-type to p-type with in-plane biaxial strain. The results suggest that there is a potential application of graphene/ WS 2 heterostructures in Schottky devices.

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“…At present, many nanomaterials behave quite excellent in the innovation of planar materials, especially the “light capture” characteristic of the array structure makes it attract attention in the field of solar cells with high light absorption . Nanowire arrays have been proven to be applicable to fields such as photocathodes and field emission cathodes . When such a nanoarray structure is applied to graded compositional Al x Ga 1−x N photocathode, not only effective light absorption can be performed, thereby ensuring sufficient photo‐generated carriers to escape, but also the advantage of short electron‐transmission distance brought by the gradient bandgap can be retained .…”

Section: Introductionmentioning

confidence: 99%

The effective light‐harvesting performance of graded compositional Al _x Ga _1−x N nano‐cone arrays photocathode for ultraviolet detector—A numerical investigation and simulation

Liu

Zhangyang

et al. 2020

Int J Energy Res

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A graded compositional Al x Ga 1−x N nanomaterial with a built-in electric field has been proposed to improve the quantum efficiency of the negative electronic affinity photocathode. When the graded compositional Al x Ga 1−x N nano-cone array is applied to the ultraviolet (UV) detector, it is necessary to improve the effective light absorption, which is high absorption in the UV short-wavelength and high sensitivity in the threshold wavelength. Therefore, the light absorption of nano-cone arrays with different feature sizes and geometrical properties is accurately calculated innovatively based on the finite-difference time-domain method. Studies show that a non-close-packed six-sided pyramid structure with a fill factor of 42.44% and a height of 1000 nm has an absorption spectrum that better satisfies the response characteristics of the UV detector. Surface reflection depends to a large extent on the transformation of the angle of incidence. The optical absorption properties of the graded compositional Al x Ga 1−x N nano-cone array provide flexibility and reference value for the improvement of the absorption coefficient and other parameters in the actual quantum efficiency experiment of the UV photocathode with built-in electric field, which can realize the highest sensitivity of various designed UV detector optical system.

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Adsorption of alkali-metal atoms on GaN nanowires photocathode

Cited by 58 publications

References 33 publications

Alkali-metal-adsorbed g-GaN monolayer: ultralow work functions and optical properties

Alkali-metal-adsorbed g-GaN monolayer: ultralow work functions and optical properties

Effect on Schottky Barrier of Graphene/WS₂ Heterostructure With Vertical Electric Field and Biaxial Strain

The effective light‐harvesting performance of graded compositional Al _x Ga _1−x N nano‐cone arrays photocathode for ultraviolet detector—A numerical investigation and simulation

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Adsorption of alkali-metal atoms on GaN nanowires photocathode

Cited by 58 publications

References 33 publications

Alkali-metal-adsorbed g-GaN monolayer: ultralow work functions and optical properties

Alkali-metal-adsorbed g-GaN monolayer: ultralow work functions and optical properties

Effect on Schottky Barrier of Graphene/WS2 Heterostructure With Vertical Electric Field and Biaxial Strain

The effective light‐harvesting performance of graded compositional Al x Ga 1−x N nano‐cone arrays photocathode for ultraviolet detector—A numerical investigation and simulation

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Product

Resources

About

Effect on Schottky Barrier of Graphene/WS₂ Heterostructure With Vertical Electric Field and Biaxial Strain

The effective light‐harvesting performance of graded compositional Al _x Ga _1−x N nano‐cone arrays photocathode for ultraviolet detector—A numerical investigation and simulation