Browsing by Author "Chang, J. -R."

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Electrically driven nanoarrow array green LED
(2012)
Chang, J. -R.
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Chang, S. -P.
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Chen, Y. -C.
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Sou, K. -P.
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Cheng, Y. -J.
An electrically driven nanopyramid green light emitting diode (LED) was demonstrated. The nanopyramid arrays were fabricated from a GaN substrate by patterned nanopillar etch, pillar side wall passivation, and epitaxial regrowth. Multiple quantum wells were selectively grown on the facets of the nanopyramids. The fabricated LED emits green wavelength under electrical injection. The emission exhibits a less carrier density dependent wavelength shift and higher internal quantum efficiency as compared with a reference c-plane sample at the same wavelength. It shows a promising potential for using nanopyramid in high In content LED applications.
Electrically driven nanopyramid green light emitting diode
(2012-02-06)
Chang, S. -P.
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Chen, Y. -C.
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Huang, J. -K.
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Cheng, Y. -J.
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Chang, J. -R.
An electrically driven nanopyramid green light emitting diode (LED) was demonstrated. The nanopyramid arrays were fabricated from a GaN substrate by patterned nanopillar etch, pillar side wall passivation, and epitaxial regrowth. Multiple quantum wells were selectively grown on the facets of the nanopyramids. The fabricated LED emits green wavelength under electrical injection. The emission exhibits a less carrier density dependent wavelength shift and higher internal quantum efficiency as compared with a reference c-plane sample at the same wavelength. It shows a promising potential for using nanopyramid in high In content LED applications. (C) 2012 American Institute of Physics. [doi:10.1063/1.3681363]
Fabrication and luminescent properties of core-shell InGaN/GaN multiple quantum wells on GaN nanopillars
(2012-06-25)
Chang, J. -R.
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Chang, S. -P.
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Li, Y. -J.
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Cheng, Y. -J.
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Sou, K. -P.
Core-shell InGaN/GaN multiple quantum wells (MQWs) on GaN nanopillars were fabricated by top-down etching followed by epitaxial regrowth. The regrowth formed hexagonal sidewalls and pyramids on the nanopillars. The cathodoluminescence of MQWs blue shifts as the location moves from top to bottom on both the pillar sidewalls and pyramid facets, covering a spectral linewidth of about 100 nm. The MQWs on the pillar sidewalls have a higher InN fraction than those on the pyramid facets. The photoluminescent wavelength is stable over two orders of carrier density change due to the smaller quantum confined Stark effect on the nanopillar facets. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4731629]
Optical properties of self assembled GaN polarity inversion domain boundary
(2011-07-11)
Liu, M. -C.
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Cheng, Y. -J.
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Chang, J. -R.
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Hsu, S. -C.
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Chang, C. -Y.
We report the fabrication of GaN lateral polarity inversion heterostructure with self assembled crystalline inversion domain boundaries (IDBs). The sample was fabricated by two step molecular-beam epitaxy (MBE) with microlithography patterning in between to define IDBs. Despite the use of circular pattern, hexagonal crystalline IDBs were self assembled from the circular pattern during the second MBE growth. Both cathodoluminescent (CL) and photoluminescent (PL) measurements show a significant enhanced emission at IDBs and in particular at hexagonal corners. The ability to fabricate self assembled crystalline IDBs and its enhanced emission property can be useful in optoelectronic applications. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3610449]