White light from annealed porous silicon: Broadband emission from violet to the near infrared

Marin, Oscar; Gennaro, Ana María; Tirado, Mónica; Koropecki, R. R.; Comedi, D.

doi:10.1016/j.matlet.2015.03.003

Cited by 4 publications

(1 citation statement)

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“…Since the relaxation of metastable phases occurs through atomic scale rearrangements, formation or annihilation of point defects is expected during this process, leading to changes in photoluminescence spectra. UV irradiation induced evolution of photoluminescence in different materials, such as porous silicon [24], polypyrrole [25] and TiO 2 [26], has been reported. For ZnO, the evolution of the photoluminescence caused by UV irradiation has been reported to occur at cryogenic temperatures [27].…”

Section: Introductionmentioning

confidence: 99%

Metastability effects on the photoluminescence of ZnO nano-micro structures grown at low temperature and influence of the precursors on their morphology and structure

González¹,

Marin²,

Tirado³

et al. 2018

Mater. Res. Express

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Nanocrystalline ZnO films were grown on silicon substrate by hydrothermal synthesis at 125 °C, using diethanolamine as additive. A powder containing ZnO spheres, with diameters between 100 to 200 nm and formed by aggregation of ZnO nanoparticles, was also obtained as a secondary reaction product. The samples were studied by scanning electron microscopy, X-ray diffraction and photoluminescence (PL) spectroscopy. The effects of the [diethanolamine]/[Zn 2+ ] molar ratio on morphological, structural and optical properties were studied, as well as the effect of laser illumination (λ=325 nm) and annealing treatment on photoluminescence properties. The film samples exhibited a compact columnar structure, with thickness between 180 to 210 nm, which were not strongly affected by the diethanolamine concentration. The X-ray diffraction patterns from the films evidenced preferred orientation along the c-axis of the ZnO wurzite structure; while the nanospheres did not show any preferential crystalline direction. The PL spectra from the films showed large initial UV emission and a weak defect band centered in the yellow. A PL evolution while the samples were UV illuminated was observed. The relaxation of metastable phases (formed during the low temperature growth) involving the creation of point defects, is suggested. The predominance of the

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Section: Introductionmentioning

confidence: 99%