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2 μ m antimonide laser and detector materials, components and physical

Author: LinChun
Tutor: LiAiZhen
School: Shanghai Institute of Metallurgy , Chinese Academy of Sciences
Course: Microelectronics and Solid State Electronics
Keywords: molecular beam epitaxy antimonide mid-infrared laser diode photodetector
CLC: TN248
Type: PhD thesis
Year: 2001
Downloads: 263
Quote: 4
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Abstract

Since there are many important applications including gas sensing, molecular spectroscopy and pollution control for mid-infrared lasers and photodetectors working at wavelengths beyond 2pm, significant efforts have been devoted to the development of AlGaAsSb/InGaAsSb multiple quantum-well (MQW) laser diodes and InGaAsSb detectors. In this thesis, the research works were focused on these two types of devices. High quality InGaAsSb, AIGaAsSb and AIGaAsSb/InGaAsSb multiple quantum well structures have been successfully grown by solid source molecular beam epitaxy (SSMBE) on (100) GaSb substrates. The influences of growth conditions such as growth temperature on the background carrier desity of InGaAsSb are reported. The strain in AIGaAsSb cladding layer can be adjusted by varying As content. As As mole fraction increases, the strain in AIGaAsSb changes from compressive to tensile. Lattice matched AIGaAsSb layers were successfully grown. Photoluminescence (PL) measurements show that if barrier thickness exceeding a critical value, the PL intensity of AlGaAsSb strained layer MQW will drop. The critical thickness of the barrier is about l5nm. Band structures of quantum wells and some material constants are calculated. To improve the performance of 2tm lasers, we optimized the broaden waveguide structure by theoretically calculating the optical confinement factor and near field distribution. Ridge waveguide, mesa stripe and planar stripe AIGaAsSb/InGaAsSb 2 ~tm lasers were fabricated. Ridge waveguide lasers show room temperature quasi-cw laser emission at a wavelength of 2.Olptm. The threshold current is 8OmA and linear output power is greater than 15mW. A characteristic temperature of 93K is obtained. The highest operation temperature of ridge waveguide lasers is 800C. Mesa stripe lasers can works under continuous-wave mode at 185K. The highest lasing temperature under pulse operation is 270K. Planar stripe lasers with high Al content cladding layers exhibit lasing at 190K. For a AlGaAsSb/InGaAsSb MQW ridge waveguide laser chip, after more than 1000 hours room temperature non-catastrophic degradation, threshold current changes within 200/c of its initial value. We attribute the degradation to the chip packaging, soldering and increasing of nonradiative centers. Kinks in P-I curves were observed. We find as kink occurring, emission wavelength switches from 2.01tm to 1.86im. The two wavelengths correspond to E1-HH1 and E2-HH2 transitions in the QW respectively. To reduce the surface leakage current of InGaAsSb detector, we design AlGaAsSb/InGaAsSb/GaSb heterostruture PIN detectors. The noise mechanisms including Generation-Recombination noise and Auger recombintation noise were analyzed. For InGaAsSb/GaSb PIN photodetectors, a room temperature blackbody detectivity of 5.1x108 cmHz112/W and a responsivity of 37V1W were achieved. For AlGaAsSb/InGaAsSb/GaSb PIN photodetectors, a blackbody detectivity of 5.Ox 108 cm.Hz112IW and a responsivity of 78V/W were achieved. We also characterized our 2.tm lasers with these two types of detectors.

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