Cathodoluminescence of epitaxial GaN and ZnO thin films for scintillator applications

Schenk, H. P. D.; Borenstain, Shmuel I.; Berezin, A. B.; Schön, Astrid; Cheifetz, E.; Dadgar, A.; Krost, A.

doi:10.1016/j.jcrysgro.2009.06.018

Cited by 13 publications

(8 citation statements)

References 63 publications

(53 reference statements)

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“…In PL spectrum, one sharp line at 365 nm due to band-edge (exciton) emission was observed. This exciton emission was reported many times in PL and cathodeluminescence evaluations [21][22]. Compared with scintillation described later, broad lines around 420 and 550 nm were also observed.…”

Section: Methodssupporting

confidence: 78%

Evaluation of Scintillation Properties of GaN

Yanagida

Fujimoto

Koshimizu

2014

e-J. Surf. Sci. Nanotechnol.

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Optical and scintillation properties of GaN crystalline film were investigated. It showed 30-50% in-line transmittance at wavelength longer than 400 nm and intense emission appeared at 365 nm under 213 nm excitation in photoluminescence (PL) spectrum. When PL decay time was investigated under 280 and 200 nm excitation, luminescence decay time resulted few ns. In X-ray induced radioluminescence spectra, intense emission appeared at 365, 420, and 550 nm. The former one was ascribed to the exciton emission and the latter two would be due to defects related emission. Scintillation decay time of GaN was quite fast as few ns which was consistent with PL results and no slow component was observed.

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Section: Methodssupporting

confidence: 78%

Evaluation of Scintillation Properties of GaN

Yanagida

Fujimoto

Koshimizu

2014

e-J. Surf. Sci. Nanotechnol.

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“…However, with the growth of ZnS, more and more defects will be created because of its polycrystalline nature. For quantification of the radiative recombination of ultraviolet emission in G-Z-S-4 and G-Z-S-6, the bimolecular rate equation of radiative recombination in a semiconductor can be used: , where R is the radiative recombination rate, n e the electron concentration, n h the hole concentration, and B the radiative recombination coefficient, whose typical values are from about 10 –11 to 10 –9 cm 3 /s for ZnO. , Since excess carriers are generated and recombined in pairs (namely, n e = n h ), eq becomes R = Bn e 2 . This equation implies that the radiative recombination rate R in each localized trap is proportional to the square of the carrier concentration, which means that the high localized carrier concentration will lead to a high radiative recombination rate and thus intensive emission.…”

Section: Results and Discussionmentioning

confidence: 99%

“…where R is the radiative recombination rate, n e the electron concentration, n h the hole concentration, and B the radiative recombination coefficient, whose typical values are from about 10 −11 to 10 −9 cm 3 /s for ZnO. 46,47 Since excess carriers are generated and recombined in pairs (namely, n e = n h ), eq 1 becomes R = Bn e 2 . This equation implies that the radiative recombination rate R in each localized trap is proportional to the square of the carrier concentration, which means that the high localized carrier concentration will lead to a high radiative recombination rate and thus intensive emission.…”

Section: Resultsmentioning

confidence: 99%

Localized-State-Dependent Electroluminescence from ZnO/ZnS Core–Shell Nanowires–GaN Heterojunction

Wei

Fang

et al. 2018

ACS Appl. Nano Mater.

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ZnO is a very important material for excitonic ultraviolet optoelectronic devices operating above room temperature due to its wide band gap and high exciton binding energy. In this paper, the influences of different degrees of the localized state on the photoluminescence and electroluminescence properties of the ZnO/ZnS core–shell nanowires–GaN heterojunction are systematically discussed. The physical model for radiative recombination of localized carriers was proposed to explain these phenomena. Our results indicate that surface-coating of ZnS nanoparticles on ZnO nanowires (NWs) is one of the effective ways to manipulate the localized states, and only the appropriate localized state will result in the optimal optoelectronic properties.

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“…451) Previously, some challenges were done to achieve good scintillation performance of GaN, but no samples emitted bright scintillation detectable with common pulse height system. [452][453][454] Recently, high crystalline quality GaN was measured, and it showed a very high scintillation light yield with remarkably fast decay time at the blue emission wavelength. 421) Although it is still a film shape, and only low-energy photons (several tens/keV) and charged particles are detectable, if bulk shape becomes available, GaN will attract much attention.…”

Section: -16mentioning

confidence: 99%