Thin films of HfO2 and ZrO2 as potential scintillators

Kirm, M.; Aarik, Jaan; Jürgens, Meelis; Силдос, И.

doi:10.1016/j.nima.2004.08.020

Cited by 125 publications

(94 citation statements)

References 12 publications

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“…Furthermore, there are no lumines cence manifestations of HfO 2 , which has a band in the low temperature PL spectra in the region of 4.2-4.4 eV and a PL excitation band in the region of 5.8 eV [16]. In this case, the appearance of a similar band should be expected because of the sensitization in the PL excitation spectrum of Ce 3+ centers.…”

Section: Discussion Of the Experimental Resultsmentioning

confidence: 92%

Luminescence of LaBr3: Ce,Hf crystals under photon excitation in the ultraviolet, vacuum ultraviolet, and X-ray ranges

2014

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Abstract-This study has been carried out using synchrotron radiation, time resolved luminescence ultraviolet and vacuum ultraviolet spectroscopy, optical absorption spectroscopy, and thermal activation spectroscopy. It has been found that, in scintillation spectrometric crystals LaBr 3 : Ce,Hf characterized by a low hygroscopicity, along with Ce 3+ centers in regular lattice sites, there are Ce 3+ centers located in the vicinity of the defects of the crystal structure. It has also been found that the studied crystals exhibit photoluminescence (PL) of new point defects responsible for a broad band at wavelengths of 500-600 nm in the PL spectra. The minimum energy of interband transitions in LaBr 3 is estimated as E g ~ 6.2 eV. The effect of multiplication of electronic excitations has been observed in the range of PL excitation energies higher than 13 eV (more than 2E g ). Thermal activation studies have revealed channels of electronic excitation energy transfer to Ce 3+ impurity centers.

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Section: Discussion Of the Experimental Resultsmentioning

confidence: 92%

Luminescence of LaBr3: Ce,Hf crystals under photon excitation in the ultraviolet, vacuum ultraviolet, and X-ray ranges

2014

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“…6(b) because of its large band gap energy of 6.15 eV (201 nm). 27) According to the previous report, 28) the peaks and shoulders observed in Fig. 6(b) are considered to be due to Tb 3+ -containing small-size particles (235 and 240 nm) and agglomerated particles (280, 290, 310 and 330 nm).…”

Section: Jcs-japanmentioning

confidence: 79%

Preparation of undoped and Tb3+-doped fluorescent HfO2 spherical particles

Sanada¹,

Kawai²,

Nakashita³

et al. 2008

J. Ceram. Soc. Japan

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Undoped and Tb3+ -doped HfO2 spherical particles were prepared by a sol-gel method, by using hafnium tetra-t-butoxide (Hf(O-t-C4H9)4) as a precursor of hafnium dioxide, SPAN85 ® as a surfactant, mixed solvent of C2H5OH and n-C4H9OH, and H2O, followed by investigation of their structural and optical properties. Spherical particles with good morphology and comparatively high dispersibility were obtained from solutions with the molar ratio SPAN85 ® :H2O = 1:8-17.5, their sizes being 0.2-5 μm in diameter. Particles became small and aggregated when the molar ratio of H2O was more than 17.5, but became large when it was less than 8. Spherical particles heat treated at 400°C or below were amorphous, and those heat treated at 600°C or above were crystallized. Tb 3+ -doped HfO2 spherical particles showed green luminescence due to the 5 D4→ 7 FJ (J = 6, 5, 4, 3) transitions of the Tb 3+ ion, and relatively strong luminescence was observed both in dried gel particles and particles heat treated at 1000°C. These Tb 3+ -doped HfO2 spherical particles can be expected for new optical materials.

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“…3. In pure monoclinic HfO 2 single crystals this band corresponds to radiation decay of STE [7,8,9]. The PL decay kinetics of UV emission in HfO 2 contains only slow components of ms-μs ranges.…”

Section: Soft X-ray Excitationmentioning

confidence: 97%

“…Moreover, hafnium oxide shows interesting physical and chemical properties. It is widely used in optical fields because of its high refractive index, high optical transparency in the ultraviolet-infrared spectral range, and wide optical band gap (E g = 5.8-6.2 eV) [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

“…In low-temperature photoluminescence (PL) spectra of HfO 2 crystals or films the emission band of defects can be detected in the region of 2.7-3.1 eV [13][14][15]. An UV intrinsic emission band of self-trapped excitons (STE) was observed in the region of 4.4 eV [7,8,9]. Pure HfO 2 , however, becomes crystalline at temperatures lower than 500° C. For high-k gate dielectrics, an amorphous structure is always preferred because a polycrystalline film can introduce high leakage paths along grain boundaries.…”

Section: Introductionmentioning

confidence: 99%

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Intrinsic and defect related luminescence in double oxide films of Al–Hf–O system under soft X-ray and VUV excitation

Пустоваров

Smirnova

Lebedev

et al. 2016

Journal of Luminescence

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Cite this article as: V.A. Pustovarov, Т.P. Smirnova, M.S. Lebedev, V.A. Gritsenko and M. Kirm, Intrinsic and defect related luminescence in double oxide films of Al-Hf-O system under soft X-ray and VUV excitation, Journal of Luminescence, http://dx.doi.org/10. 1016/j.jlumin.2015.10.053 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Hafnia films and films mixed with alumina were grown in a flow-type chemical vapor deposition reactor with argon as a carrier gas. In addition, pure alumina films were prepared by the atomic layer deposition method. A strong emission band with the peak position at 4.4 eV and with the decay time in the μs-range was revealed for pure hafnia films. The emission peak at 7.74 eV with short nanosecond decay kinetics was observed in the luminescence spectra for pure alumina films. These emission bands were ascribed to the radiative decay of self-trapped excitons (an intrinsic luminescence) in pure HfO 2 and Al 2 O 3 films, respectively.Along with intrinsic host emission, defect related luminescence bands with a larger Stokes shift were observed. In the emission spectra of the solid solution films (x= 4; 17; 20 at.%) the intrinsic emission bands are quenched and only the luminescence of defects (an anion vacancies) was observed. Based on transformation of the luminescence spectra and nsluminescence decay kinetics, as well as changes in the time-resolved luminescence and 2 luminescence excitation spectra, the relaxation processes in the films of solid solution are discussed.

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Thin films of HfO2 and ZrO2 as potential scintillators

Cited by 125 publications

References 12 publications

Luminescence of LaBr3: Ce,Hf crystals under photon excitation in the ultraviolet, vacuum ultraviolet, and X-ray ranges

Luminescence of LaBr3: Ce,Hf crystals under photon excitation in the ultraviolet, vacuum ultraviolet, and X-ray ranges

Preparation of undoped and Tb3+-doped fluorescent HfO2 spherical particles

Intrinsic and defect related luminescence in double oxide films of Al–Hf–O system under soft X-ray and VUV excitation

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