Response-time-improved ZnO scintillator by impurity doping

Kano, Masataka; Wakamiya, Akira; Sakai, Kohei; Yamanoi, Kohei; Cadatal-Raduban, Marilou; Nakazato, Tomoharu; Shimizu, Toshihiko; Sarukura, Nobuhiko; Ehrentraut, Dirk; Fukuda, Tsuguo

doi:10.1016/j.jcrysgro.2010.10.192

Cited by 36 publications

(23 citation statements)

References 16 publications

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“…With regards to scintillator applications, a bulk ZnO single crystal has been reported to exhibit fast emission lifetime of about 1.0 ns regardless of the incident excitation [7]. The lifetimes can be improved through intentional doping with the introduction of additional quenching channels [8][9][10][11] or through the use of nanostructures with enhanced oscillator strengths [12].…”

Section: Introductionmentioning

confidence: 99%

Intense and fast UV emitting ZnO microrods fabricated by low temperature aqueous chemical growth method

Santos-Putungan

Empizo

Yamanoi

et al. 2016

Journal of Luminescence

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a b s t r a c tIntense and fast ultraviolet (UV) emitting zinc oxide (ZnO) microrods are successfully fabricated by low temperature aqueous chemical growth (ACG) method. Uniform and hexagonal microrods of varying dimensions are synthesized using different zinc acetate dihydrate (ZnAc) and hexamethelynetetramine (HMTA) molar concentration ratios. Although exhibiting broad orange emissions, the microrods have intense UV emissions with lifetimes as fast as 30-40 ps. Analyses show that there is no definite correlation between the microrod dimensions and the optical emissions. Nevertheless, with the ease on the microcrystal fabrication, these ZnO microrods with intense and fast UV emissions have potential use for future scintillator applications.

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Section: Introductionmentioning

confidence: 99%

Intense and fast UV emitting ZnO microrods fabricated by low temperature aqueous chemical growth method

Santos-Putungan

Empizo

Yamanoi

et al. 2016

Journal of Luminescence

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“…2) The ZnO crystal has a fast response time of about 1.0 ns regardless of the optical excitation source. [2][3][4] ZnO response times can be further improved by impurity doping with the introduction of additional quenching channels [5][6][7] or by the possible use of nanostructures that maximize the oscillator strength. 8) In realizing ZnO scintillator applications, the effects of radiation environments are of particular interest.…”

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confidence: 99%

Gamma-ray irradiation effects on the optical properties of bulk ZnO single crystals

Empizo

Yamanoi

Mori

et al. 2015

Appl. Phys. Express

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Hydrothermal-grown bulk ZnO single crystals are investigated before and after gamma-ray irradiation. The irradiation does not alter the optical transparency in the visible region. The gamma rays only induce modified near-band-edge UV emission with blue-shifted peaks and shortened response times. From the initial values before irradiation, the peaks shift by 5 to 6 nm, and the response times shorten by 140 to 440 ps. We attribute these observations to the radiation-induced defects on the bulk crystals. Our results nevertheless lead to the realization of shortwavelength ZnO scintillators that can be utilized in high-energy-radiation environments.

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“…Time-resolved measurements of reflection, transmission, and photoluminescence spectroscopies have been carried out by a pump-probe method on various ZnO samples, i.e., nanocrystals and single crystals. [5][6][7][8][9][10] These authors have reported that the recombination processes of the photo-generated electron-hole (e-h) pairs or excitons are enhanced by the trapping of the carriers at impurity levels in the bulk band gap. Recently, a time-resolved photoelectron spectroscopy (PES) experiments were carried out on a ZnOð10 10Þ surface to trace the relaxation process of the surface photovoltage (SPV) effect to clarify the photo-generated carrier dynamics as one of the important elementary processes.…”

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confidence: 99%

“…11 Surface-sensitive results are obtained by PES as compared to optical methods. [5][6][7][8][9][10] The temporal variation of the relaxation process was described in terms of surface e-h recombination after the carrier transfer from the internal bulk to the surface over the surface potential. Time-resolved PES measures the temporal variations of the surface potential.…”

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confidence: 99%

Electron-hole recombination on ZnO(0001) single-crystal surface studied by time-resolved soft X-ray photoelectron spectroscopy

Yukawa

Ozawa

Emori

et al. 2014

Applied Physics Letters

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Time-resolved soft X-ray photoelectron spectroscopy (PES) experiments were performed with time scales from picoseconds to nanoseconds to trace relaxation of surface photovoltage on the ZnO(0001) single crystal surface in real time. The band diagram of the surface has been obtained numerically using PES data, showing a depletion layer which extends to 1 lm. Temporal evolution of the photovoltage effect is well explained by a recombination process of a thermionic model, giving the photoexcited carrier lifetime of about 1 ps at the surface under the flat band condition. This lifetime agrees with a temporal range reported by the previous time-resolved optical experiments.

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Response-time-improved ZnO scintillator by impurity doping

Cited by 36 publications

References 16 publications

Intense and fast UV emitting ZnO microrods fabricated by low temperature aqueous chemical growth method

Intense and fast UV emitting ZnO microrods fabricated by low temperature aqueous chemical growth method

Gamma-ray irradiation effects on the optical properties of bulk ZnO single crystals

Electron-hole recombination on ZnO(0001) single-crystal surface studied by time-resolved soft X-ray photoelectron spectroscopy

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