Room temperature photoluminescence in plasma treated rutile TiO2 (110) single crystals

Tariq, Fatima; Rehman, Najeeb Ur; Akhtar, Naureen; George, Richard E.; Khan, Yaqoob; Rahman, Shams

doi:10.1016/j.vacuum.2019.108999

Cited by 8 publications

(6 citation statements)

References 51 publications

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“…intensity 530 nm–2.5 eV), 580–725 nm (2.14 eV–1.7 eV), 840 nm (1.48 eV), 990 nm (1.25 eV) and 1050 nm (1.18 eV) was revealed. Green and red emissions are usually associated with the presence of oxygen vacancies and Ti 3+ defects, respectively [ 46 , 47 ]. Oxygen vacancies can be located in a wide range of states (mid-gap), i.e., 2.269 eV (447 nm) to 2.719 eV (456 nm).…”

Section: Resultsmentioning

confidence: 99%

Optically Active TiO2:Er Thin Films Deposited by Magnetron Sputtering

et al. 2021

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Titanium dioxide photoanodes for hydrogen generation suffer from a profound mismatch between the optical absorption of TiO2 and the solar spectrum. To solve the problem of low solar-to-chemical efficiency, optically active materials are proposed. In this work, TiO2 thin films containing erbium were deposited by radio frequency RF magnetron sputtering under ultrahigh vacuum conditions UHV. Morphology, structural, optical and electronic properties were studied. TiO2:Er thin films are homogenous, with uniform distribution of Er ions and high transparency over the visible VIS range of the light spectrum. However, a profound 0.4 eV blue shift of the fundamental absorption edge with respect to undoped TiO2 was observed, which can be attributed either to the size effect due to amorphization of TiO2 host or to the onset of precipitation of Er2Ti2O7 nanocrystals. Near-infrared NIR to VIS up-conversion is demonstrated upon excitation at 980 nm, while strong green photoluminescence at 525 and 550 nm occurs upon photon absorption at 488 nm.

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Section: Resultsmentioning

confidence: 99%

Optically Active TiO2:Er Thin Films Deposited by Magnetron Sputtering

et al. 2021

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“…As the Ar plasma treatment time increased to 60 s, the optical bandgap increased by 0.07 eV from 3.47 to 3.54 eV (figure 5(c)). The increase in defects in the AZO thin film owing to the Ar ion bombardment led to an increase in the charge carrier concentration, thereby increasing the optical bandgap [40]. In contrast, as the treatment time increased in the O 2 plasma, the optical bandgap slightly decreased by 0.03 eV from 3.47 to 3.44 eV.…”

Section: Resultsmentioning

confidence: 99%

Tunable physical properties of Al-doped ZnO thin films by O₂ and Ar plasma treatments

Joo

Kim

2021

Mater. Res. Express

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Al-doped ZnO (AZO) is a promising transparent conducting oxide that can replace indium tin oxide (ITO) owing to its excellent flexibility and eco-friendly characteristics. However, it is difficult to immediately replace ITO with AZO because of the difference in their physical properties. Here, we study the changes in the physical properties of AZO thin films using Ar and O2 plasma treatments. Ar plasma treatment causes the changes in the surface and physical properties of the AZO thin film. The surface roughness of the AZO thin film decreases, the work function and bandgap slightly increase, and the sheet resistance significantly decreases. In contrast, a large work function change is observed in the AZO thin film treated with O2 plasma; however, the change in other characteristics is not significant. Therefore, the results indicate that post-treatment using plasma can accelerate the development of high-performance transparent devices.

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“…These variations in TiO 2– x CL intensity may indicate an increase in OV concentrations. It is well known that OVs can appear in a variety of charged states: (i) single ionized ( Vo • ), (ii) double ionized ( Vo •• ), and (iii) neutral state ( Vo ) . As a result of the OV arrangement, energy levels form within the band gap, which in principle contribute to different luminescence bands.…”

Section: Resultsmentioning

confidence: 99%

The Role of Lattice Defects on the Optical Properties of TiO₂ Nanotube Arrays for Synergistic Water Splitting

Machreki,

Chouki,

Tyuliev

et al. 2023

ACS Omega

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In this study, we report a facile one-step chemical method to synthesize reduced titanium dioxide (TiO 2 ) nanotube arrays (NTAs) with point defects. Treatment with NaBH 4 introduces oxygen vacancies (OVs) in the TiO 2 lattice. Chemical analysis and optical studies indicate that the OV density can be significantly increased by changing reduction time treatment, leading to higher optical transmission of the TiO 2 NTAs and retarded carrier recombination in the photoelectrochemical process. A cathodoluminescence (CL) study of reduced TiO 2 (TiO 2−x ) NTAs revealed that OVs contribute significantly to the emission bands in the visible range. It was found that the TiO 2 NTAs reduced for a longer duration exhibited a higher concentration of OVs. A typical CL spectrum of TiO 2 was deconvoluted to four Gaussian components, assigned to F, F + , and Ti 3+ centers. X-ray photoelectron spectroscopy measurements were used to support the change in the surface chemical bonding and electronic valence band position in TiO 2 . Electron paramagnetic resonance spectra confirmed the presence of OVs in the TiO 2−x sample. The prepared TiO 2−x NTAs show an enhanced photocurrent for water splitting due to pronounced light absorption in the visible region, enhanced electrical conductivity, and improved charge transportation.

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Room temperature photoluminescence in plasma treated rutile TiO2 (110) single crystals

Cited by 8 publications

References 51 publications

Optically Active TiO2:Er Thin Films Deposited by Magnetron Sputtering

Optically Active TiO2:Er Thin Films Deposited by Magnetron Sputtering

Tunable physical properties of Al-doped ZnO thin films by O₂ and Ar plasma treatments

The Role of Lattice Defects on the Optical Properties of TiO₂ Nanotube Arrays for Synergistic Water Splitting

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Room temperature photoluminescence in plasma treated rutile TiO2 (110) single crystals

Cited by 8 publications

References 51 publications

Optically Active TiO2:Er Thin Films Deposited by Magnetron Sputtering

Optically Active TiO2:Er Thin Films Deposited by Magnetron Sputtering

Tunable physical properties of Al-doped ZnO thin films by O2 and Ar plasma treatments

The Role of Lattice Defects on the Optical Properties of TiO2 Nanotube Arrays for Synergistic Water Splitting

Contact Info

Product

Resources

About

Tunable physical properties of Al-doped ZnO thin films by O₂ and Ar plasma treatments

The Role of Lattice Defects on the Optical Properties of TiO₂ Nanotube Arrays for Synergistic Water Splitting