Theoretical study of Cs adsorption on GaN(0001) surface

Du, Yu; Chang, Benkang; Wang, Xiaohui; Zhang, Junju; Li, Biao; Wang, Meishan

doi:10.1016/j.apsusc.2012.04.055

Cited by 57 publications

(17 citation statements)

References 23 publications

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“…Compared with the GaN photocathode, the AlGaN photocathode surface is 12% Al, which leads to a different optimal position of Cs adsorption. The adsorption energy of Cs atoms at the photocathode is as follows [15,16]:…”

Section: Discussionmentioning

confidence: 99%

Influence of Al fraction on photoemission performance of AlGaN photocathode

et al. 2014

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To research the photoemission performance of a transmission-mode Al(1-x)Ga(x)N photocathode, Al0.24Ga0.76N and GaN photocathodes with the same structure were activated, their spectral responses were measured using a multi-information measurement system at room temperature, and the photocathode parameters were obtained by fitting quantum efficiency curves. The results showed that both the reflective-mode and transmission-mode spectral responses of the AlGaN photocathode were lower than those of the GaN photocathode. Compared with the GaN photocathode, the short-wavelength spectral response of the Al0.24Ga0.76N photocathode was less seriously affected by lattice defects between the buffer and emission layers. The Al atom at the AlGaN photocathode surface could affect the optimal Cs adsorption position, which mainly affects the surface electron escape probability of the photocathode.

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Section: Discussionmentioning

confidence: 99%

Influence of Al fraction on photoemission performance of AlGaN photocathode

et al. 2014

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“…Our calculations are based on density functional theory(DFT) with the generalized gradient approximation (GGA) [9] as implemented in the CASTEP codes [10]. All calculations are carried in reciprocal space.…”

Section: Calculation Methods and Modelsmentioning

confidence: 99%

“…A vacuum thickness of 1.5 nm is used to avoid interaction between repeated slabs. The bottom side of the slab is saturated with pseudohydrogen atoms to prevent transfer of surface charges [17].…”

Section: Calculation Methods and Modelsmentioning

confidence: 99%

First principles calculations of the electronic structure and optical properties of (001), (011) and (111) Ga0.5Al0.5As surfaces

Yu¹,

Ge²,

Chang³

et al. 2013

Materials Science in Semiconductor Processing

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“…In this paper, eight possible Cs adsorption sites at different atomic layers are chosen for Al 0.5 Ga 0.5 As (001) surface [14], while seven high-symmetry sites are considered in the calculation model of Al 0.25 Ga 0.75 N (0001) surface. Using first-principle calculation based on density functional theory (DFT) with an ultra-soft pseudopotential method [15][16][17], the influence of Cs coverage on surface adsorption energy, work functions and dipole moments of adsorption models are investigated. This work has profound guiding significance for experimental research of Al x Ga 1-x N and Al x Ga 1-x As photocathodes.…”

Section: Introductionmentioning

confidence: 99%

Comparative Research on Cs Activation Mechanism for Al0.5Ga0.5As (001) and Al0.25Ga0.75N (0001) Surface

Shen

Chen

et al. 2015

IEEE Sensors J.

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To investigate and distinguish the difference of Cs activation mechanism on Al 0.5 Ga 0.5 As (001) and Al 0.25 Ga 0.75 N (0001) surface, plane wave with ultrasoft pseudopotential method based on first-principle density functional theory (DFT) is used. Surface adsorption energy, work function and surface dipole moments with different Cs coverage are calculated and compared. Eight possible Cs adsorption sites are chosen for the Al 0.5 Ga 0.5 As (001) surface while seven high-symmetry sites are considered in the calculation model of Al 0.25 Ga 0.75 N (0001) surface. Results show that when only one Cs atom adsorbed on two surfaces, the adsorption energies are all negative and the adsorption sites are all stable sites. The lowest work function and the most stable adsorption sites with different Cs coverage are obtained and discussed. When different amounts of Cs atoms adsorbed on two surfaces, the work function values of Al 0.25 Ga 0.75 N (0001) surface are all smaller than that of Al 0.5 Ga 0.5 As (001) surface. The work function of Al 0.5 Ga 0.5 As (001) surface decreases with the increase of Cs coverage when the Cs coverage changes from 0 monolayer (ML) to 0.75 ML, while Al 0.25 Ga 0.75 N (0001) surface achieves the smallest work function when the Cs coverage is 0.5 ML. Finally, photocurrent curves during Cs activation are recorded. The photocurrent of AlGaAs sample reaches at a peak at the time of 29 min when the Cs coverage rise at 0.75 ML, while the photocurrent of AlGaN sample achieves a peak at the time of 30 min when the Cs coverage rise at 0.5 ML, which is in well consistent with our calculation results.

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Theoretical study of Cs adsorption on GaN(0001) surface

Cited by 57 publications

References 23 publications

Influence of Al fraction on photoemission performance of AlGaN photocathode

Influence of Al fraction on photoemission performance of AlGaN photocathode

First principles calculations of the electronic structure and optical properties of (001), (011) and (111) Ga0.5Al0.5As surfaces

Comparative Research on Cs Activation Mechanism for Al<sub>0.5</sub>Ga<sub>0.5</sub>As (001) and Al<sub>0.25</sub>Ga<sub>0.75</sub>N (0001) Surface

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