Photoluminescence study of swift heavy ion (SHI) induced defect centers in sapphire

Umesh²,

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

et al. 2009

Self Cite

a b s t r a c tWe present the results of photoluminescence (PL) measurements on 100 MeV Ni 8+ ion irradiated Al 2 O 3 single crystals in the fluence range 1 × 10 11 to 5 × 10 12 ions/cm 2 . A sharp PL peaks at ∼693, 695, 707 and 730 nm are recorded with an excitation of 442 nm He-Cd laser beam. The sharp emission peaks at 693 and 695 nm are attributed to R 2 and R 1 lines of Cr 3+ ions, and they are related to the transition from 2 E g → 4 A 2g . The weaker sharp peaks called N lines appear at ∼707 nm and its origin is ascribed due to closely coupled pairs of Cr 3+ ions. The longer wavelength part of the PL spectra at ∼730 nm may be due to increase of groups of more than two Cr 3+ ions. It is observed that the broad emission band (450-650 nm) consists of four bands centered at 470, 518, 547 and 618 nm, respectively. The 470, 518 and 547 nm bands are corresponding to F 2 + , F 2 and F 2 2+ defect center, respectively. It is observed that the PL intensity of F 2 , F 2 2+ , R and N lines increases with Ni 8+ ion fluence. This can be attributed to increase in concentration of color centers responsible for luminescence through radiative recombination.

Section: Resultssupporting

confidence: 93%

“…(2) There is also possibility due to reduction of Cr 3+ to Cr 2+ valence state. Same authors [23] have studied PL of sapphire in 100 MeV Ni ions in the fluence range 1 × 10 15 to 1 × 10 17 ions/cm 2 . Two broad emission bands at 516 and 546 nm are observed.…”

Section: Resultsmentioning

confidence: 99%

Photoluminescence studies of 100MeV Ni8+ ion irradiated Al2O3 single crystals

Umesh²,

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

et al. 2009

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“…Sharp emission band with peaks at 417, 432 and 465 nm are observed in both pristine and SHI irradiated samples. Based on the studies an aluminum oxide the emission bands observed in the present work with peaks at 417, 432 and 465 nm are attributed to F, F + and F 2 + centers respectively [22,24,25]. The intensity of these emission peaks varies with the ions fluence.…”

Section: Photoluminescencesupporting

confidence: 57%

“…This defect center start aggregating once their concentration become high and gives raise to pairs of oxygen vacancies (F 2 -type center) [26]. The PL intensity decreases with higher fluence which may be attributed to annihilation of F + center resulting from a disorder and induced defect center clustering and also diffusion of defect centers [25]. SHI irradiation creates a latent track in a target material when Se exceeds a threshold value (Se th ).…”

Section: Photoluminescencementioning

confidence: 99%

Synthesis characterization and luminescence studies of 100MeV Si8+ ion irradiated sol gel derived nanocrystalline Y2O3

Lakshminarasappa

Shivaramu

Nuclear Instruments and Methods in Physics Research Section B:

et al. 2014

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a b s t r a c tNanoparticles of pure yttrium oxide (Y 2 O 3 ) have been prepared by sol gel method. The powder X-ray diffraction (PXRD) pattern of as synthesized sample showed the amorphous nature. The as synthesized Y 2 O 3 powders are annealed at 500, 600, 700, 800 and 900°C for 2 h. Y 2 O 3 powder heat treated for 600°C showed cubic phase and the crystallite sizes are found to be $13 nm. Fourier transformed infrared spectroscopy (FTIR) revealed absorption with peaks at 3434, 1724, 1525, 1400, 847, 562 and 465 cm À1 . Photoluminescence (PL) of 100 MeV Si 8+ ion irradiated samples shows emission with peaks at 417, 432, 465 nm. It is found that PL intensity increases with increasing in ion fluence up to $3 Â 10 12 ions cm À2 and then decreases with further increase in ion fluence. A well resolved thermoluminescence (TL) glow with peak at $430 K (Tm 1 ) and an unresolved TL glow with peak at $538 (Tm 2 ), 584 K (Tm 3 ) are observed in ion irradiated samples.

“…Electrolyte composition in current work excluded presence of oxalate-ions. As far as data about spectral characteristics of vacancy based centers with different charge states in single crystalline α-Al 2 O 3 is concerned it can be supposed that observed emission has intrinsic origin and can be attributed to F 2 2+ -centers (2.66 eV [24][25][26]) for G1 peak and to F 2 -centers (2.4, 2.46 eV [24][25][26], 2.38 eV [27]) for G2 one. Also, various relative concentrations of optically active centers can cause scatter of spectral and kinetic characteristics of photo-and thermally stimulated processes in aluminum oxide [28].…”

Section: Discussionmentioning

confidence: 99%

Blue photoluminescence of sponge-like highly porous alumina synthesized in hydrofluoric acid based electrolytes

Ilin

Вохминцев

Martemyanov

et al. 2017

J. Phys.: Conf. Ser.

Abstract. For the first time nanostructures of anodized aluminum oxide (AAO) were synthesized using hydrofluoric acid based electrolytes under potentiostatic mode with varied oxidation conditions. As-grown oxide layers were amorphous and had sponge-like disordered structure with ramified pores system of 50 to 300 nm diameters. All samples under daylight demonstrated blue emission with power up to 10 µW that was seen by naked eye. It was shown that integral intensity of photoluminescence (PL) emission band in 350 -650 range increases up to 7 -60 times depending on synthesis details. Observed PL spectra were approximated by superposition of two components with E max = 2.74 and 2.44 eV, FWHM = 0.63 and 0.53 eV. It was substantiated that studied emission have intrinsic origin and can be attributed to F 2 2+ -and F 2 -centers.