Browsing by Author "Liu, DC"

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980 nm InGaAs/AlGaAs quantum well lasers with extremely low beam divergence
(1996)
Yen, ST
;
Lin, G
;
Liu, DC
;
Tsai, CM
;
Lee, CP
Extremely small vertical far-field angle of InGaAs-AlGaAs quantum-well lasers with specially designed cladding structure
(1996-12-01)
Lin, G
;
Yen, ST
;
Lee, CP
;
Liu, DC
;
電子工程學系及電子研究所
We report on a very small vertical far-field angle achieved by lasers with a specially designed structure. For an InGaAs-AlGaAs quantum-well laser with a 2.5-mu m-wide ridge waveguide, the far-field pattern has a vertical far-field angle of 13 degrees and a lateral far-field angle of 8 degrees. Meanwhile, the threshold current remains acceptably low (approximate to 36 mA for a 500-mu m-long cavity), The slope efficiency of the L-I characteristic is high (>0.9 W/A) compared to that of the conventional laser.
Extremely small vertical far-field angle of InGaAs-AlGaAs quantum-well lasers with specially designed cladding structure
(1996-12-01)
Lin, G
;
Yen, ST
;
Lee, CP
;
Liu, DC
;
電子工程學系及電子研究所
We report on a very small vertical far-field angle achieved by lasers with a specially designed structure. For an InGaAs-AlGaAs quantum-well laser with a 2.5-mu m-wide ridge waveguide, the far-field pattern has a vertical far-field angle of 13 degrees and a lateral far-field angle of 8 degrees. Meanwhile, the threshold current remains acceptably low (approximate to 36 mA for a 500-mu m-long cavity), The slope efficiency of the L-I characteristic is high (>0.9 W/A) compared to that of the conventional laser.
High quality quantum dots fabricated by molecular beam epitaxy
(1996-02-01)
Lee, CP
;
Liu, DC
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Damage free quantum dots have been fabricated directly using molecular beam epitaxy. Excellent photoluminescence has been obtained and is attributed to the absence of the non-radiative recombination centers and the enhanced oscillator strength for exciton recombination due to the confinement of quantum dots. The size variation of the quantum dots has been estimated from the width of the emission peak of low temperature photoluminescence (PL). A variation of only +/- 10 Angstrom is obtained. The existence of the quantum dots has also been verified directly from the image of the dots using atomic force microscopy. The image sizes of the quantum dots agree with that estimated from the PL blue shift.
Thermal annealing of Pd/InAlAs Schottky contacts for transistor buried-gate technologies
(1998-01-01)
Chuang, HF
;
Lee, CP
;
Tsai, CM
;
Liu, DC
;
Tsang, JS
We studied the thermal reaction of Pd/In0.52Al0.48As contacts using capacitance-voltage (C-V), current-voltage, Auger electron spectroscopy, and x-ray diffraction analyses and compared the results to those for Pd/Al0.25Ga0.75As and Pd/In0.53Ga0.47As contacts. The thickness of InAlAs consumed by the reaction during annealing was calculated directly from the measured C-V profiles. Pd starts to react with InAlAs at a temperature of 100 degrees C, lower than it does with AlGaAs. For thermally annealed Pd/InAlAs and Pd/AlGaAs, both compositional and structural changes were found at the Pd/semiconductor interface. However, in heat-treated Pd/InGaAs samples, compositional changes but no structural changes were observed. (C) 1998 American Institute of Physics.
Thermal annealing of Pd/InAlAs Schottky contacts for transistor buried-gate technologies
(1998-01-01)
Chuang, HF
;
Lee, CP
;
Tsai, CM
;
Liu, DC
;
Tsang, JS
We studied the thermal reaction of Pd/In0.52Al0.48As contacts using capacitance-voltage (C-V), current-voltage, Auger electron spectroscopy, and x-ray diffraction analyses and compared the results to those for Pd/Al0.25Ga0.75As and Pd/In0.53Ga0.47As contacts. The thickness of InAlAs consumed by the reaction during annealing was calculated directly from the measured C-V profiles. Pd starts to react with InAlAs at a temperature of 100 degrees C, lower than it does with AlGaAs. For thermally annealed Pd/InAlAs and Pd/AlGaAs, both compositional and structural changes were found at the Pd/semiconductor interface. However, in heat-treated Pd/InGaAs samples, compositional changes but no structural changes were observed. (C) 1998 American Institute of Physics.