Study on the electronic structure and optical properties of different Al constituent Ga1−Al As

Yu, Xiaohua; Du, Yu; Chang, Baoxian; Ge, Zhonghao; Wang, Honggang

doi:10.1016/j.ijleo.2013.03.008

Cited by 14 publications

(5 citation statements)

References 9 publications

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“…It shows when Al component x is lower than 0.5, the Al x Ga 1 x As is a direct band gap material, while when x is equal to or higher than 0.5, it is an indirect band gap material, which is in accordance with the theory and the conclusion obtained in Ref. [23]. In general, the calculated value is lower than the literature data OE23 , this is because the band gap is excited, and in the DFT calculation process, the band gap is in ground state, consequently, the calculated value is small, which tends to be low 30%-50% or even more, but this is a common phenomenon which does not affect the theoretical analysis of the electronic structure.…”

Section: Band Gapsupporting

confidence: 91%

Comparative study on the influence of Al component at GaAlAs layer for GaAs/AlGaAs photocathode

Chang

Chen

et al. 2017

J. Semicond.

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We designed two transmission-mode GaAs/AlGaAs photocathodes with different AlxGa1−x As layers, one has an AlxGa1−xAs layer with the Al component ranging from 0.9 to 0, and the other has a fixed Al component 0.7. Using the first-principle method, we calculated the electronic structure and absorption spectrum of AlxGa1−xAs at x = 0, 0.25, 0.5, 0.75 and 1, calculation results suggest that with the increase of the Al component, the band gap of AlxGa1−xAs increases. Then we activated the two samples, and obtained the spectral response curves and quantum efficiency curves; it is found that sample 1 has a better shortwave response and higher quantum efficiency at short wavelengths. Combined with the band structure diagram of the transmission-mode GaAs/AlGaAs photocathode and the fitted performance parameters, we analyze the phenomenon. It is found that the transmission-mode GaAs/AlGaAs photocathode with variable Al component and various doping structure can form a two-stage built-in electric field, which improves the probability of shortwave response photoelectrons escaping to the vacuum. In conclusion, such a structure reduces the influence of back-interface recombination, improves the shortwave response of the transmission-mode photocathode.

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Section: Band Gapsupporting

confidence: 91%

Comparative study on the influence of Al component at GaAlAs layer for GaAs/AlGaAs photocathode

Chang

Chen

et al. 2017

J. Semicond.

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“…1. The energy loss function L is an important index which describes the energy loss of a fast electron traversing in a solid [21]. The calculated loss function of NiAl and Ni 3 Al are plotted in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…As the bridge between microcosmic physics process of electrons emission and the macroscopic electronic structures, dielectric function response the band structure and other spectral information of solids [21]. The dielectric function ε can be determined by ε=ε 1 +iε 2 , where ε 1 and ε 2 are the real part and the imaginary part of the dielectric function, respectively [22].…”

Section: Materials Science Computer and Information Technologymentioning

confidence: 99%

Newly Determined Crystal Structure and Optical Property of the Intermetallic NiAl and Ni<sub>3</sub>Al Alloys: A First-Principles Computer Simulated Investigation

Chen

2014

AMR

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Using quantum mechanics plane-wave approach based on the density functional theory, the lattice constants of NixAl at different Ni concentrations (x=1, 3) are predicted. Optical properties such as dielectric function, energy loss function and reflectivity are also investigated. Results show that with the increase of Ni constituent, the location of the peak in loss function moves to the lower energy region, but the peak height increases. At 0eV, the reflectivity increases rapidly with the Ni concentration. The reflectivity of NiAl and Ni3Al are pronounced in the UV region (not in the visible light region). The dielectric properties, namely the real and imaginary parts of the dielectric function, changed significantly with Ni constituent.

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“…First principles calculations, based on density functional theory (DFT), were carried out to optimize the structures and calculate the related electronic properties using the Vienna Ab initio Simulation Package (VASP) [ 42 ]. The projector augmented wave (PAW) method and the Perdew–Burke–Ernzerhof (PBE) functional of the generalized gradient approximation were adopted for the electron–ion interaction and exchange–correlation functional, respectively [ 43 , 44 ]. The valence electron configurations in reciprocal space are 4d 10 5s 2 5p 1 , 3d 10 4s 2 4p 1 , 3s 2 3p 1 , and 4s 2 4p 3 corresponding to In, Ga, Al, and As elements, respectively.…”

Section: Methodsmentioning

confidence: 99%

Theoretical Study on the Photoemission Performance of a Transmission Mode In0.15Ga0.85As Photocathode in the Near-Infrared Region

et al. 2023

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Benefiting from a high quantum efficiency, low thermal emittance, and large absorption coefficient, InxGa1−xAs is an excellent group III–V compound for negative electron affinity (NEA) photocathodes. As the emission layer, InxGa1−xAs, where x = 0.15, has the optimal performance for detection in the near-infrared (NIR) region. Herein, an NEA In0.15Ga0.85As photocathode with Al0.63Ga0.37As as the buffer layer is designed in the form of a transmission mode module. The electronic band structures and optical properties of In0.15Ga0.85As and Al0.63Ga0.37As are calculated based on density functional theory. The time response characteristics of the In0.15Ga0.85As photocathode have been fully investigated by changing the photoelectron diffusion coefficient, the interface recombination velocity, and the thickness of the emission layer. Our results demonstrate that the response time of the In0.15Ga0.85As photocathode can be reduced to 6.1 ps with an incident wavelength of 1064 nm. The quantum efficiency of the In0.15Ga0.85As photocathode is simulated by taking into account multilayer optical thin film theory. The results indicate that a high quantum efficiency can be obtained by parameter optimization of the emission layer. This paper provides significant theoretical support for the applications of semiconductor photocathodes in the near-infrared region, especially for the study of ultrafast responses in the photoemission process.

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Study on the electronic structure and optical properties of different Al constituent Ga1−Al As

Cited by 14 publications

References 9 publications

Comparative study on the influence of Al component at GaAlAs layer for GaAs/AlGaAs photocathode

Comparative study on the influence of Al component at GaAlAs layer for GaAs/AlGaAs photocathode

Newly Determined Crystal Structure and Optical Property of the Intermetallic NiAl and Ni<sub>3</sub>Al Alloys: A First-Principles Computer Simulated Investigation

Theoretical Study on the Photoemission Performance of a Transmission Mode In0.15Ga0.85As Photocathode in the Near-Infrared Region

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