Browsing by Author "Lai, F. I."

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Enhancement of light output power of GaN-based light-emitting diodes using a SiO(2) nano-scale structure on a p-GaN surface
(2010-06-01)
Huang, H. W.
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Lai, F. I.
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Huang, J. K.
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Lin, C. H.
;
Lee, K. Y.
GaN (gallium nitride)-based light-emitting diodes (LEDs) with a nano-scale SiO(2) structure between a transparent indium-tin oxide (ITO) layer and p-GaN were fabricated. The forward voltage at 20 mA for a GaN-based LED with a SiO(2) nano-scale structure was slightly higher than that of a conventional GaN-based LED because the total area of the p-type metal contact between the transparent ITO layer and p-GaN was smaller. However, the light output power for the GaN-based LED with a nano-scale structured SiO(2) at 20 mA was 24% higher than that for a conventional GaN-based LED structure. This increase in the light output power is mostly attributed to the scattering of light from the SiO(2) photonic quasi-crystal (PQC) layer.
Enhancement of light output power of GaN-based light-emitting diodes using a SiO2 nano-scale structure on a p-GaN surface
(2010-06-01)
Huang, H. W.
;
Lai, F. I.
;
Huang, J. K.
;
Lin, C. H.
;
Lee, K. Y.
GaN (gallium nitride)-based light-emitting diodes (LEDs) with a nano-scale SiO2 structure between a transparent indium-tin oxide (ITO) layer and p-GaN were fabricated. The forward voltage at 20 mA for a GaN-based LED with a SiO2 nano-scale structure was slightly higher than that of a conventional GaN-based LED because the total area of the p-type metal contact between the transparent ITO layer and p-GaN was smaller. However, the light output power for the GaN-based LED with a nano-scale structured SiO2 at 20 mA was 24% higher than that for a conventional GaN-based LED structure. This increase in the light output power is mostly attributed to the scattering of light from the SiO2 photonic quasi-crystal (PQC) layer.
Improved carrier injection in GaN-based VCSEL via AlGaN/GaN multiple quantum barrier electron blocking layer
(2015-10-19)
Hsieh, D. H.
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Tzou, A. J.
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Kao, T. S.
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Lai, F. I.
;
Lin, D. W.
In this report, the improved lasing performance of the III-nitride based vertical-cavity surface-emitting laser (VCSEL) has been demonstrated by replacing the bulk AlGaN electron blocking layer (EBL) in the conventional VCSEL structure with an AlGaN/GaN multiple quantum barrier (MQB) EBL. The output power can be enhanced up to three times from 0.3 mW to 0.9 mW. In addition, the threshold current density of the fabricated device with the MQB-EBL was reduced from 12 kA/cm(2) (9.5 mA) to 10.6 kA/cm(2) (8.5 mA) compared with the use of the bulk AlGaN EBL. Theoretical calculation results suggest that the improved carrier injection efficiency can be mainly attributed to the partial release of the strain and the effect of quantum interference by using the MQB structure, hence increasing the effective barrier height of the conduction band. (C) 2015 Optical Society of America
"S-shaped" Photoluminescence Emission Shift in Cu(In,Ga)Se-2 Thin Films
(2012)
Liao, Y. K.
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Kuo, S. Y.
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Lai, F. I.
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Lin, W. T.
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Hsieh, D. H.
We have utilized photoluminescence (PL) measurement to investigate carrier recombination mechanism in Cu(In,Ga)Se-2 thin films and observed an S-shaped emission shift revealed from the corresponding PL peak of near band edge transition.
Single-mode InGaAs submonolayer quantum dot photonic crystal VCSELs
(2006-08-01)
Yang, H. P. D.
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Hsu, I. C.
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Lai, F. I.
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Lin, G.
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Hsiao, R. S.
An InGaAs submonolayer ( SML) quantum dot photonic crystal vertical-cavity surface-emitting laser ( QD PhC-VCSEL) for fibre-optic applications is demonstrated for the first time. The active region of the device contains three InGaAs SML QD layers. Each of the InGaAs SML QD layers is formed by alternate deposition of InAs (< 1 ML) and GaAs. Single-fundamental-mode CW output power of 3.8 mW at 28 mA has been achieved in the 990 nm range, with a threshold current of 0.9 mA. A side-mode suppression ratio ( SMSR) larger than 35 dB has been observed over the entire current operating range.