Exploration on performance of two-dimensional GaN photocathodes with uniform-doping and variable-doping structure

2021 ◽  
Author(s):  
Liangbo Huang ◽  
Jian Tian ◽  
Lei Liu ◽  
Ruxiao Di ◽  
Zihao Zhu
Keyword(s):  
Optical Properties ◽  
Work Function ◽  
Formation Energy ◽  
Electron Transition ◽  
Two Dimensional ◽  
Density Of State ◽  
Electron Escape ◽  
The Stability ◽  
Function Density ◽  
Uniform Doping

In this paper, the properties of two-dimensional (2D) gallium nitride (GaN) photocathodes with a uniform doping and variable doping structure are studied by using Mg as a doping element based on first principles. The stability, bandstructure, work function, density of state and optical properties of the GaN bilayer and GaN trilayer in two-doped ways are investigated. The results show that formation energy of variable doping structure is less than that of the uniform doping structure, which means that the variable doping structure is more stable. At the same time, the formation energy increases with increase of layers. The pristine GaN bilayer has an indirect bandgap, while the doped GaN bilayer transforms into a direct bandgap. The impurity levels appear in a forbidden band of doped GaN trilayers, which is favorable for electron transition. The results of work function reveal that variable doping structure has lower vacuum barriers and more electron escape numbers, which proves that it can improve the quantum efficiency of photocathodes. Finally, the analysis of optical properties shows that the uniform doping structure has better optical properties than that of the variable doping structure.

First-principle study on electronic structure and optical properties of GaN nanowires with different cross-sections

2016 ◽  
Vol 30 (22) ◽  
pp. 1650136
Author(s):  
Yike Kong ◽  
Lei Liu ◽  
Sihao Xia ◽  
Honggang Wang ◽  
Meishan Wang
Keyword(s):  
Optical Properties ◽  
Cross Sections ◽  
Formation Energy ◽  
Comparative Investigation ◽  
Dielectric Constants ◽  
Cross Sectional ◽  
Gan Nanowires ◽  
Bulk Gan ◽  
Structure Density ◽  
The Stability

This paper explores the properties of intrinsic gallium nitride (GaN) nanowires (NWs) in terms of formation energy, band structure, density of state (DOS) and optical properties with plane-wave ultrasoft pseudopotential method based on first-principles. Results show that after relaxation, N atoms of the outer layers move outwards, while Ga atoms move inwards, and the relaxation of surface atomic structure appears less obvious with the increasing cross-sectional area. Comparing different cross-sections of GaN NWs, it is found that the formation energy decreases and the stability goes stronger with the increasing size. With the increasing cross-section, the bandgap is decreased. Moreover, through comparative investigation in optical properties between GaN NWs and bulk GaN, a valuable phenomenom is found that the static dielectric constants of GaN NWs are notably lower, which contributes remarkably to the excellent absorbing performance of GaN NWs.

scholarly journals Two Dimensional β-InSe with Layer-Dependent Properties: Band Alignment, Work Function and Optical Properties

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 82 ◽  
Author(s):  
David K. Sang ◽  
Huide Wang ◽  
Meng Qiu ◽  
Rui Cao ◽  
Zhinan Guo ◽  
...  
Keyword(s):  
Optical Properties ◽  
Work Function ◽  
High Performance ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Strong Dependence ◽  
Band Alignment ◽  
Thickness Variation ◽  
Two Dimensional ◽  
Electronic Band

Density functional theory calculations of the layer (L)-dependent electronic band structure, work function and optical properties of β-InSe have been reported. Owing to the quantum size effects (QSEs) in β-InSe, the band structures exhibit direct-to-indirect transitions from bulk β-InSe to few-layer β-InSe. The work functions decrease monotonically from 5.22 eV (1 L) to 5.0 eV (6 L) and then remain constant at 4.99 eV for 7 L and 8 L and drop down to 4.77 eV (bulk β-InSe). For optical properties, the imaginary part of the dielectric function has a strong dependence on the thickness variation. Layer control in two-dimensional layered materials provides an effective strategy to modulate the layer-dependent properties which have potential applications in the next-generation high performance electronic and optoelectronic devices.

Novel Janus diamane C4FCl: a stable and moderate bandgap semiconductor with huge excitonic effect

2021 ◽  
Author(s):  
Huabing Shu
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Optoelectronic Properties ◽  
The Novel ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Electronic And Optical Properties ◽  
The Stability ◽  
Excitonic Effect

Semiconducting two-dimensional Janus materials have drawn increasing attention for the novel optoelectronic properties. Here, employing first-principles calculations, we systematically explore the stability, electronic and optical properties of Janus diamane C4FCl....

scholarly journals Electronic structural critique of interesting thermal and optical properties of C17Ge germagraphene

2020 ◽  
Vol 22 (16) ◽  
pp. 8606-8615 ◽  
Author(s):  
Sujoy Datta ◽  
Debnarayan Jana
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Thermal Properties ◽  
Work Function ◽  
Hall Conductivity ◽  
Two Dimensional ◽  
Spin Hall Conductivity

We report a theoretical attempt to understand the involvement of the electronic structure in producing spin Hall conductivity and in determining the optical and thermal properties of germagraphene, a buckled two-dimensional material with low work function.

scholarly journals Electronic Structure and Optical Properties of Gaas1-Xpx: A First-Principles Study

2020 ◽  
pp. 77-82
Author(s):  
Alaa A. Al-Jobory ◽  
Wael, I. Ahmed ◽  
Ibrahim J. A.
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Charge Transfer ◽  
First Principles ◽  
Density Functional ◽  
Gallium Phosphide ◽  
Two Dimensional ◽  
Density Of State ◽  
Electrical And Optical Properties ◽  
State Band

In this work, the effects of x-value on electrical and optical properties was studied for the two dimensional (2D)GaAs1-xPxstructure by applying the density functional theory.We found that the gallium arsenide(GaAs) and gallium phosphide(GaP) monolayers are bound to each other, while the charge transfer between these two materialsleads to tuning the band gap value between 1.5 eV for GaAs to 2.24 eV for GaP. The density of state, band structure, and optical properties are investigated in this paper.

scholarly journals Polymorphic gallium for active resonance tuning in photonic nanostructures: from bulk gallium to two-dimensional (2D) gallenene

Nanophotonics ◽  
2020 ◽  
Vol 9 (14) ◽  
pp. 4233-4252
Author(s):  
Yael Gutiérrez ◽  
Pablo García-Fernández ◽  
Javier Junquera ◽  
April S. Brown ◽  
Fernando Moreno ◽  
...  
Keyword(s):  
Optical Properties ◽  
Room Temperature ◽  
Phase Change Materials ◽  
Two Dimensional ◽  
Active Materials ◽  
Promising Candidate ◽  
Plasmonic Structures ◽  
Resonance Tuning ◽  
The Many ◽  
Optical Behavior

AbstractReconfigurable plasmonics is driving an extensive quest for active materials that can support a controllable modulation of their optical properties for dynamically tunable plasmonic structures. Here, polymorphic gallium (Ga) is demonstrated to be a very promising candidate for adaptive plasmonics and reconfigurable photonics applications. The Ga sp-metal is widely known as a liquid metal at room temperature. In addition to the many other compelling attributes of nanostructured Ga, including minimal oxidation and biocompatibility, its six phases have varying degrees of metallic character, providing a wide gamut of electrical conductivity and optical behavior tunability. Here, the dielectric function of the several Ga phases is introduced and correlated with their respective electronic structures. The key conditions for optimal optical modulation and switching for each Ga phase are evaluated. Additionally, we provide a comparison of Ga with other more common phase-change materials, showing better performance of Ga at optical frequencies. Furthermore, we first report, to the best of our knowledge, the optical properties of liquid Ga in the terahertz (THz) range showing its broad plasmonic tunability from ultraviolet to visible-infrared and down to the THz regime. Finally, we provide both computational and experimental evidence of extension of Ga polymorphism to bidimensional two-dimensional (2D) gallenene, paving the way to new bidimensional reconfigurable plasmonic platforms.

Structural, electronic, and optical properties of two-dimensional hafnium monoxide nanosheets

2021 ◽  
Vol 130 ◽  
pp. 114690
Author(s):  
Xinxin Deng ◽  
Bingcheng Luo ◽  
Zili Zhang ◽  
Changchun Zhao ◽  
Mengjun Shi ◽  
...  
Keyword(s):  
Optical Properties ◽  
Two Dimensional ◽  
Electronic And Optical Properties

scholarly journals The two-dimensional hydrodynamical theory of moving aerofoils. IV

1947 ◽  
Vol 188 (1015) ◽  
pp. 439-463
Keyword(s):  
Stability Problem ◽  
Two Dimensional ◽  
Centre Of Gravity ◽  
First Approximation ◽  
Von Karman ◽  
Moving Cylinder ◽  
Period Equation ◽  
The Stability ◽  
Von Kármán ◽  
Hydrodynamical Theory

In the first part of this paper opportunity has been taken to make some adjustments in certain general formulae of previous papers, the necessity for which appeared in discussions with other workers on this subject. The general results thus amended are then applied to a general discussion of the stability problem including the effect of the trailing wake which was deliberately excluded in the previous paper. The general conclusion is that to a first approximation the wake, as usually assumed, has little or no effect on the reality of the roots of the period equation, but that it may introduce instability of the oscillations, if the centre of gravity of the element is not sufficiently far forward. During the discussion contact is made with certain partial results recently obtained by von Karman and Sears, which are shown to be particular cases of the general formulae. An Appendix is also added containing certain results on the motion of a vortex behind a moving cylinder, which were obtained to justify certain of the assumptions underlying the trail theory.

scholarly journals Tuning the optoelectronic properties of hematite with rhodium doping for photoelectrochemical water splitting using density functional theory approach

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abdur Rauf ◽  
Muhammad Adil ◽  
Shabeer Ahmad Mian ◽  
Gul Rahman ◽  
Ejaz Ahmed ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Optical Absorption ◽  
Water Splitting ◽  
Density Functional ◽  
Formation Energy ◽  
Visible Region ◽  
Photoelectrochemical Water Splitting ◽  
Theory Approach ◽  
Functional Theory

AbstractHematite (Fe2O3) is one of the best candidates for photoelectrochemical water splitting due to its abundance and suitable bandgap. However, its efficiency is mostly impeded due to the intrinsically low conductivity and poor light absorption. In this study, we targeted this intrinsic behavior to investigate the thermodynamic stability, photoconductivity and optical properties of rhodium doped hematite using density functional theory. The calculated formation energy of pristine and rhodium doped hematite was − 4.47 eV and − 5.34 eV respectively, suggesting that the doped material is thermodynamically more stable. The DFT results established that the bandgap of doped hematite narrowed down to the lower edge (1.61 eV) in the visible region which enhanced the optical absorption and photoconductivity of the material. Moreover, doped hematite has the ability to absorb a broad spectrum (250–800) nm. The enhanced optical absorption boosted the photocurrent and incident photon to current efficiency. The calculated results also showed that the incorporation of rhodium in hematite induced a redshift in optical properties.

Auxetic, flexible, and strain-tunable two-dimensional th-AlN for photocatalytic visible light water splitting with anisotropic high carrier mobility

2021 ◽  
Vol 9 (14) ◽  
pp. 4971-4977
Author(s):  
Mehmet Emin Kilic ◽  
Kwang-Ryeol Lee
Keyword(s):  
Optical Properties ◽  
Visible Light ◽  
Water Splitting ◽  
Carrier Mobility ◽  
Two Dimensional ◽  
Light Water ◽  
Photocatalytic Water Splitting ◽  
Electronic And Optical Properties ◽  
High Carrier Mobility ◽  
High Carrier

Tetrahexagonal AlN: a novel two-dimensional family for photocatalytic water splitting with exceptional mechanical, electronic, and optical properties.

Sign in / Sign up

Export Citation Format

Share Document