Luminescence studies of Ti-doped Al2O3 using vacuum ultraviolet synchrotron radiation

Mikhailik, V.B.; Kraus, H.; Wahl, David; Mykhaylyk, M. S.

doi:10.1063/1.1880451

Cited by 25 publications

(25 citation statements)

References 14 publications

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“…18,20,21 The emission spectra of the studied samples measured at T ¼ 300 and 8 K are shown in Fig. 1.…”

Section: Resultsmentioning

confidence: 99%

“…In the 6.2-9.2 eV range these excitation spectra are very similar to the excitation spectra monitored at 290 nm, which is consistent with the results of our earlier measurements. 18,20 However in the 5.0-6.2 eV range there is noticeable difference in their appearance. The excitation spectra of lightly doped samples exhibit a steplike bump peaking at $6.1 eV, while those with titanium concentration !100 ppm show a gradual rise of intensity from 5.0 to 6.2 eV.…”

Section: -3mentioning

confidence: 95%

“…Recent studies of the 290 nm band have assigned this emission to the radiative decay of excitons localized at activator ions. 18,20 The prominent feature of the emission spectra at excitation with 7.1 eV photons is the characteristic blue band at 420 nm in lightly doped Al 2 O 3 ÀTi, which is absent in the samples with Ti concentration !100 ppm.…”

Section: -2mentioning

confidence: 99%

“…This reproduces well the excitation spectrum of ultraviolet emission in Al 2 O 3 ÀTi reported earlier. 18,20 The excitation spectra of the 325 nm band measured in Ti-doped and anion-deficient crystals of Al 2 O 3 are displayed in Fig. 3.…”

Section: -2mentioning

confidence: 99%

“…This prompted a systematic investigation of the emission properties of sapphire as a function of temperature, excitation conditions and Ti concentration. 18,[20][21][22] It has been shown that these studies on the concentration dependence can help explain the origin of the ubiquitous emission of Al 2 O 3 . This motivated further systematic investigations of the emission and excitation spectra of aluminum oxide with different concentration of Ti as well as anion-deficient Al 2 O 3 using vacuum ultraviolet (VUV) synchrotron radiation.…”

Section: Introductionmentioning

confidence: 99%

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Studies of concentration dependences in the luminescence of Ti-doped Al2O3

Mikhailik

Stefano

Henry

et al. 2011

Journal of Applied Physics

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The variation of luminescence and excitation spectra of titanium doped Al 2 O 3 for the concentration of Ti ranging from 10 to 1000 ppm was investigated using synchrotron radiation. In the lightly doped Al 2 O 3 -Ti (<100 ppm) samples we identified several emission bands. These are the emission of the excitons localized at Ti (290 nm), the emission due to F þ centers (325 nm), the band around 420 nm traditionally attributed to F center emission, and the luminescence of Ti 3þ ions at 720 nm. The emphasis in this study is on the clarification of the nature of the blue emission band in the samples with high concentration of Ti (!100 ppm), where the luminescence and excitation spectra of the blue emission exhibit noticeable variability. This is explained by a model of the luminescence process of Ti 4þ -F centers that includes the photoionization of Ti 3þ , the subsequent capture of electrons at F þ -centers, formation of excited F-centers and, finally, the emission of a blue photon. The quenching of the blue emission with increasing Ti concentration is interpreted in terms of competition between oxygen vacancies and Ti 4þ centers in the capture of the electron.

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“…18,20,21 The emission spectra of the studied samples measured at T ¼ 300 and 8 K are shown in Fig. 1.…”

Section: Resultsmentioning

confidence: 99%

Section: -3mentioning

confidence: 95%

Section: -2mentioning

confidence: 99%

Section: -2mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Studies of concentration dependences in the luminescence of Ti-doped Al2O3

Mikhailik

Stefano

Henry

et al. 2011

Journal of Applied Physics

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Fabrication and Light‐Emission Study of Ti‐δ‐Doped Quasi‐2D γ‐Alumina by Graphene‐Assisted Atomic Layer Deposition

2023

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Crystalline quasi‐2D Ti‐δ‐doped γ‐alumina (2D‐Ti:γ‐alumina) is synthesized by a facile, precursor‐alternating atomic‐layer‐deposition technique followed by a post‐growth air‐anneal at ≈800 °C. According to energy‐dispersive X‐ray spectroscopy maps, Ti atomic concentration remains uniform and approaches ≈1.5%. Subject to several UV‐light exposures, the samples are found to develop a full strength, stable emission in the ultrawide spectral range of ≈350–850 nm. The near‐infrared (NIR) emission band centered at ≈760 nm is assigned to Ti deep defect states introduced in the alumina host. According to photoluminescence excitation–emission studies, aggregate oxygen vacancies remain a primary excitation source of the NIR emission. In addition, a broad visible‐range emission band at ≈525 nm is registered in the temperature range of ≈108–348 K, but unlike the NIR band, its temperature dependence remains Arrhenius with the non‐radiative recombination activation energy of ≈73 ± 9 meV. The resultant 2D‐Ti:γ‐alumina holds promise for applications in low‐cost alumina‐based optoelectronics, photocatalytic remediation, and spectrally wide light sources.

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Lanthanide and Heavy Metal Free Long White Persistent Luminescence from Ti Doped Li–Hackmanite: A Versatile, Low‐Cost Material

Norrbo

Carvalho

Laukkanen

et al. 2017

Adv Funct Materials

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Persistent luminescence (PeL) materials are used in everyday glow‐in‐the‐dark applications and they show high potential for, e.g., medical imaging, night‐vision surveillance, and enhancement of solar cells. However, the best performing materials contain rare earths and/or other heavy metal and expensive elements such as Ga and Ge, increasing the production costs. Here, (Li,Na)8Al6Si6O24(Cl,S)2:Ti, a heavy‐metal‐ and rare‐earth‐free low‐cost material is presented. It can give white PeL that stays 7 h above the 0.3 mcd m−2 limit and is observable for more than 100 h with a spectrometer. This is a record‐long duration for white PeL and visible PeL without rare earths. The material has great potential to be applied in white light emitting devices (LEDs) combined with self‐sustained night vision using only a single phosphor. The material also exhibits PeL in aqueous suspensions and is capable of showing easily detectable photoluminescence even in nanomolar concentrations, indicating potential for use as a diagnostic marker. Because it is excitable with sunlight, this material is expected to additionally be well‐suited for outdoor applications.

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Luminescence studies of Ti-doped Al2O3 using vacuum ultraviolet synchrotron radiation

Cited by 25 publications

References 14 publications

Studies of concentration dependences in the luminescence of Ti-doped Al2O3

Studies of concentration dependences in the luminescence of Ti-doped Al2O3

Fabrication and Light‐Emission Study of Ti‐δ‐Doped Quasi‐2D γ‐Alumina by Graphene‐Assisted Atomic Layer Deposition

Lanthanide and Heavy Metal Free Long White Persistent Luminescence from Ti Doped Li–Hackmanite: A Versatile, Low‐Cost Material

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