Browsing by Author "Liang, CY"

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Continuous-wave high-power (320 mW) single mode operation of electronic vertically coupled InAs/GaAs quantum dot narrow-ridge-waveguide lasers
(2005-12-01)
Wang, JS
;
Lin, G
;
Hsiao, RS
;
Yang, CS
;
Lai, CM
High-power 3 mu m-wide narrow-ridge-waveguide lasers with ten stacks of electronic vertically coupled InAs/GaAs quantum dots in the active region were demonstrated. Unlike that from conventional uncoupled InAs quantum dot lasers, a narrow lasing spectrum was observed because the carriers tunneled in the vertical direction. Continuous-wave operation in single lateral mode yielded a kink-free output power of 320 mW with an efficiency of 0.46 W/A , and a sensitivity of lasing wavelength to temperature of 0.28 nm/K.
Improvements of amorphous-silicon inverted-staggered thin-film transistors using high-temperature-deposited Al gate with chemical mechanical polishing
(2000-05-01)
Shih, PS
;
Chang, TC
;
Liang, CY
;
Huang, TY
;
Chang, CY
Chemical mechanical polished Al (CMP-Al) films deposited at various temperatures were explored as the gate electrodes of amorphous- silicon (a-Si:H) inverted-staggered thin-film transistors (TFTs) for the first time. Although the surface roughness of the as-deposited Al films increased with increasing deposition temperature, Al films deposited at higher temperature were more robust to hillock formation during subsequent annealing. To take advantage of the better hillock suppression properties, CMP is employed to reduce the inherently large surface roughness of these high-temperature-deposited Al films. Our results show that the electrical characteristics of the TFTs are significantly improved. Specifically, the threshold voltage is reduced from 2.37 to 1.43 V, the mobility is improved from 0.32 to 1.36 cm(2)/V s, and the subthreshold swing is improved from 0.72 to 0.58 V/decade as the Al deposition temperature is increased from 25 to 400 degrees C. (C) 2000 The Electrochemical Society. S1099-0062(99)10-107-X. All rights reserved.
Molecular-beam-epitaxy growth of high-quality InGaAsN/GaAs quantum well lasers emitting at 1.3 mu m
(2004-11-01)
Wang, JS
;
Hsiao, RS
;
Lin, G
;
Lin, KF
;
Liu, HY
Molecular-beam-epitaxy growth of high structural and optical-quality InGaAsN/GaAs quantum wells (QW) has been investigated. The material quality can be improved significantly by using low-temperature growth to suppress the phase separation. High-performance ridge-waveguide InGaAsN/GaAs single QW lasers emitting at 1.3 mum have been demonstrated. Infinite-cavity-length threshold-current density of 400 A /cm(2), internal quantum efficiency of 96%. and a slope efficiency of 0.67 W/A for a cavity length L=1 mm were obtained. A TO46 packaging laser shows sin-le lateral-mode kink-free output power of more than 200 mW with a maximum total wallplug efficiency of 29% at room temperature under continuous wave (cw) operation. Moreover. 1.3 Am InGaAsN/GaAs QW vertical-cavity surface-emitting lasers with a threshold current density lower than 2 KA/cm(2) at room temperature have been achieved. We obtained multimode cw output power and slope efficiency in excess of 1 mW and 0.15 W/A. respectively. (C) 2004 American Vacuum Society.
Single mode 1.3 mu m InGaAsN/GaAs quantum well vertical cavity surface emitting lasers grown by molecular beam epitaxy
(2004-12-01)
Hsiao, RS
;
Wang, JS
;
Lin, KF
;
Wei, L
;
Liu, HY
The growth by molecular-beam-epitaxy of high-quality 1.3 mum InGaAsN/GaAs quantum wells (QW) intra-cavity contacted vertical cavity surface emitting lasers (VCSELs) was demonstrated. Low-temperature growth, which suppresses the phase separation significantly improves material quality in the active region. Room-temperature continuous wave (RT-CW) single mode output power of 0.75 mW with an initial slope efficiency of 0.17 W/A and a side mode suppression ratio of 40 dB at a lasing wavelength of as long as 1304 nm were obtained.