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Title: Strong green emission in ZnO films after H2 surface treatment
Authors: Li, T.
Herng, T. S.
Liang, H. K.
Bao, N. N.
Wong, J. I.
Xue, J. M.
Chen, Tupei
Ding, Jun
Keywords: DRNTU::Engineering::Electrical and electronic engineering
Issue Date: 2012
Source: Li, T., Herng, T. S., Liang, H. K., Bao, N. N., Chen, T., Wong, J. I., et al. (2012). Strong green emission in ZnO films after H 2 surface treatment. Journal of physics D : applied physics, 45(18).
Series/Report no.: Journal of physics D : applied physics
Abstract: Using a two-step fabrication technique (pulsed laser deposition (PLD) and H2 surface treatment), we fabricated ZnO thin films that could emit ultra-strong green emission with coexistence of random lasing phenomenon. After PLD deposition, the as-prepared undoped ZnO thin films (200–500 nm) were annealed in Ar 95%–H25% ambient at 500 °C. The H2 treatment led to the formation of a porous structure that creates substantial optical cavities (diameter ~1.3 µm). Surprisingly, these optical cavities tremendously amplified the green emission rather than ultraviolet (UV) emission. There was insignificant change in emission intensity after high-temperature annealing (700 °C) in O2 and acetone dipping, indicating the samples are thermally and chemically stable. The samples exhibited a high quantum yield of 32%. We studied the origin of this ultra-strong green emission using low-temperature photoluminescence, extensive structural study and cyclic annealing. The results suggested that neither hydrogen nor VO plays a role in green emission. The green emission was attributed mainly to the complex defects and the presence of structural defects in the porous structure. In addition, we demonstrated the feasibility of large-scale green emission ZnO fabrication via micro-size patterning, paving a way to practical optoelectronic applications.
DOI: 10.1088/0022-3727/45/18/185102
Rights: © 2012 IOP Publishing Ltd.
Fulltext Permission: none
Fulltext Availability: No Fulltext
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