Enhanced Photoluminescence and Raman Properties of Al-Doped ZnO Nanostructures Prepared Using Thermal Chemical Vapor Deposition of Methanol Assisted with Heated Brass

Thandavan, Tamil Many K.; Gani, Siti Meriam Abdul; Wong, C. S.; Nor, Roslan Md

doi:10.1371/journal.pone.0121756

Cited by 71 publications

(31 citation statements)

References 66 publications

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“…In addition, raman inactive B 2 mode at 276 cm -1 is observed for AZO films due to the built in electric dipole. The presence of enhanced raman signal at around 276 cm -1 confirms substitution of Al in ZnO 29 .…”

Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 71%

“…It is known that, the peak at 440 cm -1 generally originates from the E 2 (High) mode of ZnO associated with the wurtzite structure. The peak at 575 cm -1 is a contribution of the E 1 (LO) mode of ZnO associated with the O vacancies, Zn i or the combination of both [28][29] . This peak appears to be broad, asymmetric in nature and more spread on lower wave number side is observed, which indicates that the reduction of oxygen deficiency in AZO films with increase of RF power 28 .…”

Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 99%

“…7 that, the NBE emission peak is red shifted due to Al doping. It could be due to the combined effect of an optical transition to the excitonic state of ZnO and electronic transitions involving in crystal-field splitting 29 . On the other hand, the peak positions of other peaks 435, 460 and 492 nm remains unaffected.…”

Section: Photoluminescence (Rt and Lt)mentioning

confidence: 99%

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Effect of RF power on the structural, optical and gas sensing properties of RF-sputtered Al doped ZnO thin films

Srinatha

Kamble³

et al. 2016

RSC Adv.

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The effect of Radio Frequency (RF) power on the properties of magnetron sputtered Al doped ZnO thin films and the related sensor properties are investigated. A series of 2 wt% Al doped ZnO; Zn0.98Al0.02O (AZO) thin films prepared with magnetron sputtering at different RF powers, are examined. The structural results reveal a good adhesive nature of thin films with quartz substrates as well as increasing thickness of the films with raising RF power. Besides, the increasing RF power is found to improve the crystallinity and grains growth as confirmed by X-ray diffraction. On the other hand, the optical transmittance is significantly influenced by the RF power, where the transparency values achieved are higher than 82% for all the AZO thin films and the estimated optical band gap energy is found to decrease with RF power due to an increase in the crystallite size as well as the film thickness. In addition, the defect induced luminescence at low temperature (77 K) and room temperature (300 K) was studied through photoluminescence spectroscopy, it is found that the defect density of electronic states of Al 3+ ion found to increase with increase of RF power due to the increase in the thickness of the film and the crystallite size. The gas sensing behavior of AZO films was studied for NO2 at 350 °C. The AZO film shows good response towards NO2 gas and also a good relationship between the response and the NO2 concentration, which is modeled using an empirical formula. The sensing mechanism of NO2 is discussed.

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Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 71%

Section: Scanning Electron Microscopy (Sem)mentioning

confidence: 99%

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Effect of RF power on the structural, optical and gas sensing properties of RF-sputtered Al doped ZnO thin films

Srinatha

Kamble³

et al. 2016

RSC Adv.

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“…Due to overtones or combination of first‐order modes, the second‐order features were identified as 2TA = 208 cm −1 ,

E_{2}^{high} - E_{2}^{low}

= 340 cm −1 , TO + LO = 1090 cm −1 , 2LO = 1150 cm −1 . A weak Raman peak located at 735 cm −1 for samples doped by Ti was assigned to the A 1g mode involved in the titanium zinc spinel phase in TiO 2 doped samples (ZnO:Ti, ZnO:TiMg, ZnO:AlTi, ZnO:AlTiMg) . The Raman bands detected at 574 cm −1 and 584 cm −1 in all samples correspond to A 1 (LO) and E 1 (LO) modes associated to structural disorder or lattice defects such as oxygen vacancies, Zn interstitials and their combination as suggested from the strong dependence of these bands on the oxygen stoichiometry .…”

Section: Resultsmentioning

confidence: 82%

“…33 The nonpolar E 2 consists of two modes, namely, E high 2 at high frequency and mainly associated with oxygen displacement characterizing the wurtzite lattice, and the low frequency E low 2 mainly associated to the Zn sub-lattice. 34 For the assignment of the Raman spectra, the modes were first normalized according to the E 36 The Raman bands detected at 574 cm −1 and 584 cm −1 in all samples correspond to A 1 (LO) and E 1 (LO) modes associated to structural disorder or lattice defects such as oxygen vacancies, Zn interstitials and their combination as suggested from the strong dependence of these bands on the oxygen stoichiometry. 35,37 Besides, in contrast to other doping ions, Al doped samples Electron paramagnetic resonance and NMR are local probe techniques able to give precise assignment on the coordination of defined chemical elements, such as paramagnetic doping ions or electronic active centers by EPR and local order of Al and Zn ions by NMR.…”

Section: And Discussionmentioning

confidence: 99%

Co‐doping effects of (Al, Ti, Mg) on the microstructure and electrical behavior of ZnO‐based ceramics

Sun

Tian

et al. 2020

J Am Ceram Soc

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Co‐doped ZnO‐based ceramics using Al, Ti, and Mg ions in different ratios were synthesized with the objective to investigate the doping effects on the crystalline features, microstructure and the electrical behavior. For Al and Ti doping, a coexistence of crystalline phases was shown with a major wurtzite ZnO structure and secondary spinel phases (ZnAl2O4, Zn2TiO4, or ZnaTibAlcOd), while Mg doping did not alter significantly the structural features of the wurtzite ZnO phase. The electrical behavior induced by Al, Ti, and Mg co‐doping in different ratios was investigated using Raman, electron paramagnetic resonance (EPR) and 27Al and 67Zn solid‐state nuclear magnetic resonance (NMR). Al doping induces a high electrical conductivity compared to other doping elements. In particular, shallow donors from Zni‐AlZn defect structures are inferred from the characteristic NMR signal at about 185 ppm; that is, quite far from the usual oxygen coordinated Al. The Knight shift effect emanating from a highly conducting Al‐doped ZnO ceramics was considered as the origin of this observation. Oppositely, as Ti doping leads to the formation of secondary spinel phases, EPR analysis shows a high concentration of Ti3+ ions which limit the electrical conductivity. The correlation between the structural features at the local order, the involved defects and the electrical behavior as function of the doping process are discussed.

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Growth of Aluminum Doped Zinc Oxide Nanostructure Thin Films by Nonconventional Sol‐Gel Method

Alrefaee

Singh

Das

2022

Macromolecular Symposia

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The present work demonstrates the growth of undoped and Al doped ZnO (AZO) thin films by using nonconventional sol-gel method. The structural, morphological, optical, and electrical properties of obtained thin films are studied. X-ray diffraction (XRD) analysis confirms hexagonal wurtzite structures for both undoped and doped thin films. The crystallite size is found between 15 and 30 nm. Scanning electron microscope (SEM) images show that the films have approximately uniform morphologies, consisting in several flower-like aggregates with nanosized multipetals. From the optical properties, it is found that with the increase in the doping concentration, there is a decrease in the absorption coefficient in the visible wavelength range. It is also noticed that the increase in doping concentration causes an increase in bandgap (E g ) and a decrease in extinction coefficient. Urbach energy decreases with increase in the doping concentration. In the Hall effect study, it is observed that the conductivity and carrier concentration increase sharply with increasing the aluminum quantity. The causes and significance of these observations are discussed.

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Enhanced Photoluminescence and Raman Properties of Al-Doped ZnO Nanostructures Prepared Using Thermal Chemical Vapor Deposition of Methanol Assisted with Heated Brass

Cited by 71 publications

References 66 publications

Effect of RF power on the structural, optical and gas sensing properties of RF-sputtered Al doped ZnO thin films

Effect of RF power on the structural, optical and gas sensing properties of RF-sputtered Al doped ZnO thin films

Co‐doping effects of (Al, Ti, Mg) on the microstructure and electrical behavior of ZnO‐based ceramics

Growth of Aluminum Doped Zinc Oxide Nanostructure Thin Films by Nonconventional Sol‐Gel Method

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