Browsing by Author "Hsiao, Ru-Shang"

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A novel dilute antimony channel In0.2Ga0.8AsSb/GaAs HEMT
(2007-02-01)
Su, Ke-Hua
;
Hsu, Wei-Chou
;
Lee, Ching-Sung
;
Wu, Tsung-Yeh
;
Wu, Yue-Han
This letter reports, for the first time, a high-electron mobility. transistor (HEMT) using A dilute antimony In0.2Ga0.8AsSb channel, which is grown by a molecular-beam epitaxy system. The interfacial quality within the InGaAsSb/GaAs quantum well of the HEMT device was effectively improved by introducing the surfactantlike Sb atoms during the growth of the InGaAs layer. The improved heterostructural quality and electron transport properties have also been verified by various surface characterization techniques. In comparison, the proposed HEMT with (without) the incorporation of Sb atoms has demonstrated the maximum extrinsic transconductance g(m,max) of 227 (180) mS/mm, a drain saturation current density I-DSS of 218 (170) mA/mm, a gate-voltage swing of 1.215 (1.15) V, a cutoff frequency f(T) of 25 (20.6) GHz, and the maximum oscillation frequency f(max) of 28.3 (25.6) GHz at 300 K with gate dimensions of 1.2 x 200 mu m(2).
Beam profile characteristics of InGaAs sub-monolayer quantum-dot photonic-crystal VCSELs
(2007-06-01)
Yang, Hung-Pin D.
;
Hsu, I-Chen
;
Lai, Fang-I
;
Lin, Gray
;
Hsiao, Ru-Shang
An InGaAs sub-monolayer (SML) quantum dot photonic crystal vertical-cavity surface-emitting laser (QD PhC-VCSEL) for fiberoptic applications is first time demonstrated. The active region of the device contains 3 InGaAs SML QD layers. Each of the InGaAs SML QD layer 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. Side-mode suppression ratio (SMSR) larger than 35 dB has been demonstrated over entire current operation range. The beam profile study of the PhC-VCSEL indicates that the laser beam is well confined by the photonic crystal structure of the device. The divergence angle of the devices remains almost unchanged with increasing current. (C) 2007 Elsevier B.V. All rights reserved.
Characteristics of broad-area InGaAs submonolayer quantum-dot vertical-cavity surface-emitting lasers
(2007-10-01)
Yang, Hung-Pin D.
;
Hsu, I-Chen
;
Lai, Fang-I
;
Lin, Gray
;
Hsiao, Ru-Shang
A broad-area InGaAs submonolayer (SML) quantum-dot vertical-cavity surface-emitting laser (QD VCSEL) for fiber-optic applications is demonstrated. The active region of the device contains three InGaAs SML QD layers. Each of the InGaAs SML QD layers is formed by alternate depositions of InAs (< 1 ML) and GaAs. A maximum CW output power of 12.2 mW at 30 mA has been achieved in the 990 nm range, with a threshold current of 1 mA.
Characteristics of InGaAs submonolayer quantum-dot and InAs quantum-dot photonic-crystal vertical-cavity surface-emitting lasers
(2008-05-01)
Yang, Hung-Pin D.
;
Hsu, I. -Chen
;
Chang, Ya-Hsien
;
Lai, Fang-I
;
Yu, Hsin-Chieh
We have made InGaAs submonolayer (SML) quantum-dot (QD) and InAs QD photonic-crystal vertical-cavity surface-emitting lasers (PhC-VCSELs) for fiber-optic communications in the 990 and 1300 nm ranges, respectively. The active region of the InGaAs SML QD PhC-VCSEL contains three InGaAs SML QD layers, with each of the SML QD layer formed by alternating depositions of InAs (< 1 ML) and GaAs. The active region of the InAs QD PhC-VCSEL contains 17 undoped InAs-InGaAs QD layers. Both types of QD PhC-VCSELs exhibit single-mode characteristics throughout the current range, with side-mode suppression ratio (SMSR) larger than 35 dB. A maximum output power of 5.7 mW has been achieved for the InGaAs SML QD PhC-VCSEL. The near-field image study of the QD PhC-VCSELs indicates that the laser beam is well confined by the photonic-crystal structure of the device.
Characteristics of single-mode InGaAs sub-monolayer quantum-dot photonic-crystal VCSELs emitting in the 990 nm range
(2008)
Yang, Hung-Pin D.
;
Hsu, I. -Chen
;
Lai, Fang-I.
;
Lin, Gray
;
Hsiao, Ru-Shang
We have made InGaAs sub-monolayer (SML) quantum dot photonic crystal vertical-cavity surface-emitting lasers (QD PhC-VCSELs) for fiber-optic applications. The active region of the device contains three InGaAs SML QD layers. Each of the InGaAs SML QD layer 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. Side-mode suppression ratio (SMSR) larger than 35 dB has been demonstrated over the entire current operation range. Near-field images of the PhC-VCSELs were also measured and studied.
Characteristics of single-mode InGaAs submonolayer quantum-dot photonic-crystal vertical-cavity surface-emitting lasers
(2006-12-01)
Yang, Hung-Pin D.
;
Hsu, I-Chen
;
Lai, Fang-I
;
Lin, Gray
;
Hsiao, Ru-Shang
An InGaAs submonolayer (SML) quantum-dot photonic-crystal vertical-cavity surface-emitting laser (QD PhC-VCSEL) for fiber-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 depositions of InAs (< 1 ML) and GaAs. A 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 demonstrated over the entire current operation range. The beam profile and near-field image study of the PhC-VCSEL indicates that the laser beam,is well confined by the photonic crystal structure of the device.
Evolution of carrier distribution and defects in InGaAsN/GaAs quantum wells with composition fluctuation
(2006-07-01)
Chen, Jenn-Fang
;
Hsiao, Ru-Shang
;
Hsieh, Pei-Chen
;
Chen, Yu-Chih
;
Wang, Jyh-Shyang
Carrier distribution and defect induction in In0.34Ga0.66As0.98N0.02/GaAs-single quantum wells grown by molecular beam epitaxy at low growth rates are investigated by frequency-dependent capacitance-voltage (C-V) and deep-level transient spectroscopy (DLTS). The C-V studies show that lowering the growth rate of the InGaAsN layer splits the carrier accumulation in the well into a central and two side peaks with different frequency dispersions. The DLTS studies show that a continuum of states (0-0.083eV) and a,deep trap at 0.21-0.25eV are responsible for the central and the side peaks, respectively. A comparison with photoluminescence (PL) spectra shows that these defects are induced by composition fluctuation. Lowering the growth rate degrades composition fluctuation by segregating the material into an InGaAsN phase and an N-depleted phase. Post-growth annealing can remove the deep trap and improve the InGaAsN emission, confirming that the deep trap degrades the InGaAsN phase. The feature of the continuum of states suggests that it may be the structural defects associated with lattice expansion or localized states introduced by composition fluctuation.
Investigations on highly stable thermal characteristics of a dilute In(0.2)Ga(0.8)AsSb/GaAs doped-channel field-effect transistor
(2008-04-01)
Su, Ke-Hua
;
Hsu, Wei-Chou
;
Lee, Ching-Sung
;
Hu, Po-Jung
;
Wu, Yue-Han
This work reports for the first time a novel In(0.2)Ga(0.8)AsSb/GaAs heterostructure doped-channel field-effect transistor (DCFET) grown by the molecular beam epitaxy system. The interfacial quality within the InGaAsSb/GaAs quantum well of the DCFET device has been effectively improved by introducing surfactant-like Sb atoms during the growth of the Si-doped InGaAs channel layer. The improved device characteristics include the peak extrinsic transconductance (g(m, max)) of 161.5 mS mm(-1), the peak drain-source saturation current density (IDSS, max) of 230 mA mm(-1), the gate-voltage swing (GVS) of 1.65 V, the cutoff frequency (f(T)) of 12.5 GHz and the maximum oscillation frequency (f(max)) of 25 GHz at 300 K with the gate dimensions of 1.2 x 200 mu m(2). The proposed design has also shown a stable thermal threshold coefficient (partial derivative V(th)/partial derivative T) of -0.7 mV K(-1).