Browsing by Author "Huang, Ji-Kai"

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Large Area of Ultraviolet GaN-Based Photonic Quasicrystal Laser
(2012-04-01)
Chen, Cheng-Chang
;
Chiu, Ching-Hsueh
;
Tu, Po-Min
;
Kuo, Ming-Yen
;
Shih, M. H.
In this study, large-area GaN-based photonic quasicrystal (PQC) nanopillars were fabricated on an n-GaN substrate using the nanoimprint lithography (NIL) technique. Under optical pumping condition, a high lasing action from the GaN photonic quasicrystals was observed. The lasing wavelength is at 366nm with a low threshold power density of 0.009 kW/cm(2). To confirm the band-edge lasing mode, the finite-element method (FEM) was used to perform the simulation for the 12-fold symmetry photonic quasicrystal lattices. (C) 2012 The Japan Society of Applied Physics
Large-area ultraviolet GaN-based photonic quasicrystal laser with high-efficiency green color emission of semipolar {10-11} In0.3Ga0.7N/GaN multiple quantum wells
(2013-01-07)
Chen, Cheng-Chang
;
Chiu, Ching-Hsueh
;
Chang, Shih-Pang
;
Shih, M. H.
;
Kuo, Ming-Yen
In this study, a multi-color emission was observed from the large-area GaN-based photonic quasicrystal (PQC) nanopillar laser. The GaN PQC nanostructure was fabricated on an n-GaN layer by using nanoimprint lithographic technology. The regrown InGaN/GaN multiple quantum wells (MQWs) formed a nanopyramid structure on top of the PQC nanopillars. A lasing action was observed at ultraviolet wavelengths with a low threshold power density of 24 mJ/cm(2), and a green color emission from InGaN/GaN MQWs was also achieved simultaneously. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4775373]
Lasing action in gallium nitride quasicrystal nanorod arrays
(2012-05-21)
Chang, Shih-Pang
;
Sou, Kuok-Pan
;
Chen, Chieh-Han
;
Cheng, Yuh-Jen
;
Huang, Ji-Kai
We report the observation of lasing action from an optically pumped gallium nitride quasicrystal nanorod arrays. The nanorods were fabricated from a GaN substrate by patterned etching, followed by epitaxial regrowth. The nanorods were arranged in a 12-fold symmetric quasicrystal pattern. The regrowth grew hexagonal crystalline facets and core-shell multiple quantum wells (MQWs) on nanorods. Under optical pumping, multiple lasing peaks resembling random lasing were observed. The lasing was identified to be from the emission of MQWs on the nanorod sidewalls. The resonant spectrum and mode field of the 12-fold symmetric photonic quasicrystal nanorod arrays is discussed. (C) 2012 Optical Society of America