White-light emission from annealed ZnO:Si nanocomposite thin films

Shabnam,; Kant, Chhaya Ravi; Arun, P.

doi:10.1016/j.jlumin.2012.01.051

Cited by 25 publications

(11 citation statements)

References 22 publications

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“…This red component could be boosted by annealing in oxygen, facilitating a greater density of surface oxygen, possibly at the expense of OH surface moieties (see below). Interestingly, a good red PL yield (and thus a better white output) has recently been achieved with more complex ZnO-silicon nanocomposite structures [46] where appeal is made to the ZnO grain-Si interface region, specifically to Zn-Si-O linkages and thence to the eventual formation of ZnSiO 4 , to explain spectral peaks centred at 420 and 640 nm, respectively. However, these peak wavelengths are almost exactly coincident with two of the peaks observed in the ZnO-NS here and may, therefore, be subject to characterisation in terms of only the ZnO material itself.…”

Section: Resultsmentioning

confidence: 99%

One-step synthesis of ZnO nanosheets: a blue-white fluorophore

2012

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Zinc oxide is synthesised at low temperature (80°C) in nanosheet geometry using a substrate-free, single-step, wet-chemical method and is found to act as a blue-white fluorophore. Investigation by atomic force microscopy, electron microscopy, and X-ray diffraction confirms zinc oxide material of nanosheet morphology where the individual nanosheets are polycrystalline in nature with the crystalline structure being of wurtzite character. Raman spectroscopy indicates the presence of various defects, while photoluminescence measurements show intense green (centre wavelength approximately 515 nm) blue (approximately 450 nm), and less dominant red (approximately 640 nm) emissions due to a variety of vacancy and interstitial defects, mostly associated with surfaces or grain boundaries. The resulting colour coordinate on the CIE-1931 standard is (0.23, 0.33), demonstrating potential for use as a blue-white fluorescent coating in conjunction with ultraviolet emitting LEDs. Although the defects are often treated as draw-backs of ZnO, here we demonstrate useful broadband visible fluorescence properties in as-prepared ZnO.

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Section: Resultsmentioning

confidence: 99%

One-step synthesis of ZnO nanosheets: a blue-white fluorophore

2012

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“…The enhancement in the intensity of NBE emission (UV luminescence) in the Sr doped samples (ZSr1, ZSr3) can be attributed to the raise in crystallite size. [46][47][48][49][50][51][52] Relative intensity of the visible range luminescence in the range 400-600 nm is enhanced with increase in the Sr doping due to the formation of more defects by the random substitution of Sr and also favored by the relaxation in micro strain. 43 The high Sr doped sample (ZSr5) shows near-white light emission when compared with undoped ZnO sample (ZSr0).…”

Section: Optical Absorption Studiesmentioning

confidence: 99%

“…Nonradiative transitions in ZnO favored by the high doping content of Sr might be the reason for the intensity fall in the ZSr5 sample when compared with the remaining two doped samples (ZSr1 and ZSr3). [50][51][52] The color maps of the excitation dependent studies (see supplementary material, Fig. S4 53 ) provide good understanding of the luminescence variation with doping concentration.…”

Section: Optical Absorption Studiesmentioning

confidence: 99%

Role of micro-strain and defects on band-gap, fluorescence in near white light emitting Sr doped ZnO nanorods

Udayabhaskar¹,

Karthikeyan²

2014

Journal of Applied Physics

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We report tunable band gap (red shift in band gap) of ZnO driven by the Sr doping. It is observed that enhanced white light like luminescence from Sr doped ZnO nanorods. Raman studies have carried out to get insight of phonon related vibrational properties. Dopant induced local vibrational mode appeared after Sr incorporation has been identified from Raman studies. Photoluminescence studies show that doped ZnO nanorods fluorescence covers the entire visible region apart from the characteristic exciton related UV luminescence. Crystallite size variation, defects formation, and relaxation of micro strain after doping shows a strong dependence on the luminescence of the prepared samples. The increase in luminescence with increasing dopant concentration is attributed to doping induced changes in crystallinity, micro strain, and defects formation in the samples.

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“…Zinc Oxide (ZnO), as a non-toxic and bio-compatible semiconductor material, with a wide band gap (3.37 eV) and high exciton binding energy (60 meV) at room temperature, has been widely investigated as gas sensor [1][2][3][4], solar cells [5][6][7], fluorescence enhancing [8], light emitting devices [9], polariton lasers [10,11] and so on. Hitherto, such as spheres [12,1,2,13], nanorods [14][15][16], nanosheets [17,18], nanowires [19], nanowhiskers [5] and nanotubes [20,21] have been explored.…”

Section: Introductionmentioning

confidence: 99%