Photoluminescence of Cr3+ in nanostructured Al2O3 synthesized by evaporation using a continuous wave CO2 laser

Kostyukov, Anton I.; Baronskiy, Mark G.; Rastorguev, A. A.; Снытников, В. Н.; Zhuzhgov, Aleksey V.; Ищенко, А. В.

doi:10.1039/c5ra19455e

Cited by 25 publications

(10 citation statements)

References 33 publications

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“…[32][33][34]62 While the change in both PL and transmission due to implantation spans over a large range of wavelengths, interestingly, the characteristic Cr 3+ impurity peak shown in Figure 3b is unaffected by the implantation process, hence suggesting a wider energy distribution of trap states in the bandgap as compared to atomic transition levels. 63,64 As a result, the implantation process results in a broad photoluminescence band, which is in agreement with what has been reported for ion-implanted Al 2 O 3 . 33 The luminescence of the implanted regions is higher than that of pristine sapphire at shorter wavelengths (see the curves for 532 and 633 nm excitation wavelengths in Figure 3a): this suggests the formation of optically active defect states deep in the oxide bandgap.…”

Section: ■ Results and Discussionsupporting

confidence: 90%

“…These measurements supporting the argument for the ion damage-induced formation of trap states within the oxide bandgap 47,48 . While the change in both PL and transmission due to implantation spans over a large range of wavelengths, interestingly, the characteristic Cr 3+ impurity peak shown in Figure 3b is unaffected by the implantation process, hence suggesting a wider energy distribution of trap states in the bandgap, as compared to atomic transition levels 49,50 .…”

Section: Charge Transportmentioning

confidence: 99%

See 1 more Smart Citation

Giant Conductivity Modulation of Aluminum Oxide Using Focused Ion Beam

Bianconi¹,

Park²,

Mohseni

2019

ACS Appl. Electron. Mater.

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Precise control of the conductivity of semiconductors through doping has enabled the creation of advanced electronic devices, similarly, the ability to control the conductivity in oxides can enable novel advanced electronic and optoelectronic functionalities. While this was successfully shown for moderately insulating oxides, such as In 2 O 3 , a reliable method for increasing the conductivity of highly insulating, wide bandgap dielectrics, such as aluminum oxide (Al 2 O 3 ), has not been reported yet. Al 2 O 3 is a material of significant technological interest, permeating diverse fields of application, thanks to its exceptional mechanical strength and dielectric properties. Here we present a versatile method for precisely changing the conductivity of Al 2 O 3 . Our approach greatly exceeds the magnitude of the best previously reported change of conductivity in an oxide (In 2 O 3 ). With an increase in conductivity of about 14 orders of magnitude, our method presents about 10 orders of magnitude higher change in conductivity than the best previously reported result. Our method can use focused ion beam to produce conductive zones with nanoscale resolution within the insulating Al 2 O 3 matrix. We investigated the source of conductivity modulation and identified trap-assisted conduction in the ion damage-induced defects as the main charge transport mechanism. Temperature-dependency of the conductivity and optical characterization of the patterned areas offer further insight into the nature of the conduction mechanism. We also show that the process is extremely reproducible and robust against moderate annealing temperatures and chemical environment. The record conductivity modulation, combined with the nanoscale patterning precision allows the creation of conductive zones within a highly insulating, mechanically hard, chemically inert, and bio-compatible matrix, which could find broad applications in electronics, optoelectronics, and medical implants.Aluminum oxide (Al 2 O 3 ) is one of the most widely employed dielectric materials, thanks to its excellent insulating properties 1 , mechanical hardness and resistance 2 , and biocompatibility 2,3 , with applications ranging from device passivation 1,4-8 , MOSFET gate 9-13 , to biomedical implants and antifouling passivation 2,3,14,15 . Electrical functionalization of Al 2 O 3 via reliable and spatially-accurate control of its conductivity could enable novel sensing technologies encompassing electrical contacts embedded in a mechanically hard, chemically inert, and electrically insulating dielectric matrix. Examples of such technological applications include photon emission and detection 7,16-19 , low-energy in-terconnects 20-22 , energy conversion 1,23,24 , and implantable devices [25][26][27] . We here present an effective method for the non-subtractive nanopatterning of electrically conductive wires and other features embedded in a dielectric Al 2 O 3 substrate, using focused ion beam (FIB). While patterning of nanowires in transparent conductive In 2 O 3 has been ...

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Section: ■ Results and Discussionsupporting

confidence: 90%

Section: Charge Transportmentioning

confidence: 99%

Giant Conductivity Modulation of Aluminum Oxide Using Focused Ion Beam

Bianconi¹,

Park²,

Mohseni

2019

ACS Appl. Electron. Mater.

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“…4A2 in Cr 3þ ions of the -Al 2 O 3 matrix (the R1 and R2 lines), whereas for oxidation temperatures at 700 C, curves have a pronounced maximum at about max ¼ 694 nm. This shift was shown by Kostyukov et al [53][54][55] The PL results of PM2000 alloy oxidized at 700 C, and that oxidized at 1200 C re°ects the di®erences of oxides formed at each temperature. The results of antecedent work 55 have shown that at 700 C, the various oxides formed are essentially Fe 2 O 3 , Cr 2 O 3 and Al 2 O 3 .…”

Section: Photoluminescence Spectroscopysupporting

confidence: 54%

Characterization by Photoluminescence and Raman Spectroscopy of the Oxide Scales Grown on the PM2000 at High Temperatures

Hakkar

Achache

Sanchette

et al. 2019

J. Mol. Eng. Mater.

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The microstructural change of a thermal oxidation on a PM2000 superalloy was investigated after a 48 h isothermal heat-treatment. The oxides (transitions aluminas, [Formula: see text]-alumina and mixed oxides) were characterized using the Raman spectroscopy, the Photoluminescence (PL) spectroscopy, MEB observations and the X-ray diffraction for temperatures between 600°C and 1200°C. The X-ray diffraction results under conventional incidence conditions make it possible to estimate the crystallites size and the specific surfaces of the [Formula: see text]-alumina. The PL analyses at various excitation wavelengths (200[Formula: see text]nm, 234[Formula: see text]nm, 326[Formula: see text]nm and 532[Formula: see text]nm) provide important information on the existing defects (intrinsic and extrinsic) according to the oxidation temperature. The Raman spectroscopy ([Formula: see text].18[Formula: see text]nm) gives the various signatures of the various alumina generated ([Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text]-Al2O3).

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“…In excitation (PLE) spectra (Figure 8a), bands at 325 nm corresponded to the PZ and/or Al 2 O 3 substrate and to charge transfer bands (CTB) and also to the spin‐allowable Cr 3+ changes, respectively. [ 25,26 ] The PLE spectra for Cr 3+ (λ em = 614 and 714 nm) exhibited broad bands at 403 and 545 nm, which were attributed to spin‐allowed transitions from the 4 A 2 ground state to the 4 T 1 and 4 T 2 excited states, respectively. [ 27,28 ] The small band at 475 nm was linked to the 4 A 2 → 2 T 2 spin forbidden transition.…”

Section: Resultsmentioning

confidence: 99%

“…In Figure 7 and also to the spin-allowable Cr 3+ changes, respectively. [25,26] The PLE spectra for Cr 3+ (λ em = 614 and 714 nm) exhibited broad bands at 403 and 545 nm, which were attributed to spin-allowed transitions from the 4 A 2 ground state to the 4 T 1 and 4 T 2 excited states, respectively. [27,28] The small band at 475 nm was linked to the 4 A 2 !…”

Section: Morphological Characteristics Of Filmsmentioning

confidence: 99%

Luminescence properties of neodymium, samarium, and europium niobate and tantalate thin films

et al. 2022

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Thin films of lanthanide orthoniobate LnNbO4 (LnNO) and orthotantalate LnTaO4 (LnTO), (Ln = Nd, Sm, Eu) were fabricated using the sol–gel method with subsequent spin‐coating on the PbZrO3/Al2O3 substrate and annealing at 1000°C. X‐ray diffraction patterns showed monoclinic M‐LnNbO4 or M´‐LnTaO4, which coexists with the orthorhombic or tetragonal phase. X‐ray photoelectron spectroscopy demonstrated the presence of Nd3+, Sm3+/Sm2+ and Eu3+/Eu2+ ions. The luminescence properties of polymorphic films were investigated. Excitation spectra of PbZrO3 interlayer represented broad bands at 410 and 550 nm that were assigned to charge transfer bands (CTB). In all films, the CTB broad band at ~275 nm related to charge transfer transition of Ln3+→O2− and NbO43− or TaO43− groups. In excitation spectra, 4I9/2→4G5/2 (Nd3+), 6H5/2→6P3/2 (Sm3+) and 7F0→5L6 (Eu3+) transitions (at 585, 402 and 395 nm), respectively were found to be more intense than any other Ln3+ transition. The emission spectra showed narrow and intense bands at 1065, 600, and 614 nm that were ascribed to Nd3+, Sm3+, and Eu3+ 4f–f intraconfigurational transitions 4F3/2→4I11/2, 4G5/2→6H7/2, and 5D0→7F2, respectively. The excellent luminescence properties of films make them new potential groups for visible and/or near‐infrared applications such as sensors and imaging equipment.

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Photoluminescence of Cr³⁺ in nanostructured Al₂O₃ synthesized by evaporation using a continuous wave CO₂ laser

Abstract: Photoluminescence of Cr3+ in nanostructured α-Al2O3 synthesized by evaporation using a continuous wave CO2 laser.

Cited by 25 publications

References 33 publications

Giant Conductivity Modulation of Aluminum Oxide Using Focused Ion Beam

Giant Conductivity Modulation of Aluminum Oxide Using Focused Ion Beam

Characterization by Photoluminescence and Raman Spectroscopy of the Oxide Scales Grown on the PM2000 at High Temperatures

Luminescence properties of neodymium, samarium, and europium niobate and tantalate thin films

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