Damage coefficient associated with free exciton lifetime in GaAs irradiated with neutrons and electrons

Parenteau, M.; Carlone, C.; Khanna, Shyam M.

doi:10.1063/1.350884

Cited by 21 publications

(11 citation statements)

References 14 publications

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“…This is attributed to the irradiation induced decrease in exciton lifetime because of the presence of non-radiative centres. A similar observation in GaAs has been made by Parenteau et al 38 Interestingly, the photoresponse partially recovers after 16 h of irradiation which is found to recover completely within a day. Such a recovery of the spectral response is attributed to the room temperature annealing of irradiation induced defects states.…”

Section: à3supporting

confidence: 86%

Effect of 60Co γ-irradiation on the nature of electronic transport in heavily doped n-type GaN based Schottky photodetectors

Chatterjee

Khamari

Porwal

et al. 2018

Journal of Applied Physics

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GaN Schottky photodetectors are fabricated on heavily doped n-type GaN epitaxial layers grown by the hydride vapour phase epitaxy technique. The effect of 60Co γ-radiation on the electronic transport in GaN epilayers and Schottky detectors is studied. In contrast to earlier observations, a steady rise in the carrier concentration with increasing irradiation dose is clearly seen. By considering a two layer model, the contribution of interfacial dislocations in carrier transport is isolated from that of the bulk layer for both the pristine and irradiated samples. The bulk carrier concentration is fitted by using the charge balance equation which indicates that no new electrically active defects are generated by γ-radiation even at 500 kGy dose. The irradiation induced rise in the bulk carrier concentration is attributed to the activation of native Si impurities that are already present in an electrically inert form in the pristine sample. Further, the rise in interfacial contribution in the carrier concentration is governed by the enhanced rate of formation of nitrogen vacancies by irradiation, which leads to a larger diffusion of oxygen impurities. A large value of the characteristic tunnelling energy for both the pristine and irradiated Au/Ni/GaN Schottky devices confirms that the dislocation-assisted tunnelling dominates the low temperature current transport even after irradiation. The advantage of higher displacement energy and larger bandgap of GaN as compared to GaAs is evident from the change in leakage current after irradiation. Further, a fast recovery of the photoresponse of GaN photodetectors after irradiation signifies their compatibility to operate in high radiation zones. The results presented here are found to be crucial in understanding the interaction of 60Co γ-irradiation with n+-GaN epilayers.

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Section: à3supporting

confidence: 86%

Effect of 60Co γ-irradiation on the nature of electronic transport in heavily doped n-type GaN based Schottky photodetectors

Chatterjee

Khamari

Porwal

et al. 2018

Journal of Applied Physics

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“…Figure 2 shows calculated optical spectra of GaAs and solid Ne obtained from the Dyson equation using the LRC kernel with α = Aα RPAB , where A is a scaling factor, and compares them with experiment. 44,49 We chose GaAs and solid Ne because they are extreme examples of semiconductors with weakly bound Wannier-Mott excitons and insulators with strongly bound Frenkel excitons. In the case of GaAs, the optical spectrum shows two prominent peaks above the band gap; E 1 can be interpreted as a continuum exciton.…”

Section: A Comparison Of Lrc α-Parametersmentioning

confidence: 99%

Assessment of long-range-corrected exchange-correlation kernels for solids: Accurate exciton binding energies via an empirically scaled bootstrap kernel

Byun

Ullrich

2017

Phys. Rev. B

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In time-dependent density-functional theory, a family of exchange-correlation kernels, known as long-range-corrected (LRC) kernels, have shown promise in the calculation of excitonic effects in solids. We perform a systematic assessment of existing static LRC kernels (empirical LRC, Bootstrap, and jellium-with-a-gap model) for a range of semiconductors and insulators, focusing on optical spectra and exciton binding energies. We find that no LRC kernel is capable of simultaneously producing good optical spectra and quantitatively accurate exciton binding energies for both semiconductors and insulators. We propose a simple and universal, empirically scaled Bootstrap kernel which yields accurate exciton binding energies for all materials under consideration, with low computational cost.

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“…Here and in Table 2, if not specified we use the following parameters for the local and LR kernels: A = 1, ε = 1. The experimental values for the exciton binding energies are 1.51-4.9 meV (the heavy-hole energy is larger, around 5 meV) [45,46]. −0.00001…”

Section: XCmentioning

confidence: 98%

“…In the linear response theory approximation in the case of weak pulses one can put in these equations n ck (t) = 1, n vk (t) = 0. Then, in the parabolic band approximation Equation (45) in the frequency representation transforms to:…”

Section: Semiconductor Bloch Equations and The Wannier Equationmentioning

confidence: 99%

Time-Dependent Density-Functional Theory and Excitons in Bulk and Two-Dimensional Semiconductors

2017

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Abstract:In this work, we summarize the recent progress made in constructing time-dependent density-functional theory (TDDFT) exchange-correlation (XC) kernels capable to describe excitonic effects in semiconductors and apply these kernels in two important cases: a "classic" bulk semiconductor, GaAs, with weakly-bound excitons and a novel two-dimensional material, MoS 2 , with very strongly-bound excitonic states. Namely, after a brief review of the standard many-body semiconductor Bloch and Bethe-Salpether equation (SBE and BSE) and a combined TDDFT+BSE approaches, we proceed with details of the proposed pure TDDFT XC kernels for excitons. We analyze the reasons for successes and failures of these kernels in describing the excitons in bulk GaAs and monolayer MoS 2 , and conclude with a discussion of possible alternative kernels capable of accurately describing the bound electron-hole states in both bulk and two-dimensional materials.

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Damage coefficient associated with free exciton lifetime in GaAs irradiated with neutrons and electrons

Cited by 21 publications

References 14 publications

Effect of 60Co γ-irradiation on the nature of electronic transport in heavily doped n-type GaN based Schottky photodetectors

Effect of 60Co γ-irradiation on the nature of electronic transport in heavily doped n-type GaN based Schottky photodetectors

Assessment of long-range-corrected exchange-correlation kernels for solids: Accurate exciton binding energies via an empirically scaled bootstrap kernel

Time-Dependent Density-Functional Theory and Excitons in Bulk and Two-Dimensional Semiconductors

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