Browsing by Author "Wei, L"

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Characterization of self-assembled InAs quantum dots with InAlAs/InGaAs strain-reduced layers by photoluminescence spectroscopy
(2005-04-15)
Chang, KP
;
Yang, SL
;
Chuu, DS
;
Hsiao, RS
;
Chen, JF
The optoelectronic characteristics of self-assembled InAs quantum dots (QDs) with strain-reduced layers (SRLs) were investigated using photoluminescence (PL) spectroscopy. Various SRLs that combine In0.14Al0.86As and In0.14Ga0.86As with the same total thickness were examined to ascertain their confining effect on carriers in InAs QDs. The emission wavelength is blueshifted as the thickness of InAlAs is increased. The energy separation between the ground state and the first excited state of QDs with InAlAs SRLs greatly exceeds that of QDs with InGaAs SRLs. Atomic force microscopic images and PL spectra of the QD samples demonstrated that high-quality InAs QDs with long emission wavelengths and a large energy separation can be generated by growing a low-temperature, thin InAlAs SRL onto self-assembled QDs. (C) 2005 American Institute of Physics.
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.