Extremely low threshold operation of 1.5 mu m GaInAsP/InP buried ridge stripe lasers

1.5 mu m Fabry-Perot lasers exhibiting extremely low threshold currents have been obtained with a buried ridge stripe (BRS) structure. Threshold currents are 5.7 and 15.5 mA for 300 mu m and 1 mm cavity lengths, respectively, in CW operation. The optical losses of the buried waveguide have been determined from the external quantum efficiency dependence with cavity length.<>     

Room temperature continuous-wave operation of quantum-cascade lasers grown by metal organic vapour phase epitaxy

Quantum cascade lasers grown by metal organic vapour phase epitaxy are demonstrated to work in continuous mode up to room temperature. The lasers have been processed as buried heterostructures with thick gold plating on the top contact. Continuous-wave output powers of 20 mW are obtained at 300 K with threshold current densities of 3.9 kA/cm/sup 2/.     

Room temperature operation of ultra-short quantum cascade lasers with deeply etched Bragg mirrors

Mid-infrared GaAs based bound-to-continuum quantum cascade microlasers with ridge waveguide geometry are fabricated by the monolithic integration of deeply etched semiconductor-air Bragg mirrors. Devices with ultra-short cavities of 50 and 150 /spl mu/m can be operated near room temperature (260 K) or at room temperature (300 K), respectively. 50 /spl mu/m-long devices show singlemode emission up to relatively high drive currents due to the large mode spacing of about 30 cm/sup -1/ (340 nm).     

Room-temperature continuous-wave operation of long wavelength (l ?9.5 lm) MOVPE-grown quantum cascade lasers

High-power continuous-wave operation of long wavelength quantum cascade lasers grown by metal organic vapour phase epitaxy is reported. The lasers have been processed as buried heterostructures with thick gold-plated contacts. The devices emit at a wavelength of 9.5 mum with output powers of several hundreds of milliwatts at room temperature.     

Room temperature, continuous-wave lasing near 1300 nm in microdisks with quantum dot active regions

Room temperature, optically-pumped, continuous-wave lasing near 1300 nm in microdisk resonant cavities with InAs quantum dot active regions is reported for the first time. Lasing occurred in devices with diameters between 6 and 7 /spl mu/m with incident threshold pumping powers as low as 2 mW     

Room temperature (34°C) operation of strain-compensated quantumcascade lasers

A short wavelength (λ-3.5 μm) strain-compensated In_xGa_(1-x)As/In_yAl_(1-y)As quantum cascade laser is reported. Quasi-continuous wave operation of this device at 34°C with an output power of 11.4 mW persisted for more than 30 minutes without obvious degradation. A very low threshold current density of 1.2 KA/cm² at this temperature was observed     

Design of quantum well AlGaAs-GaAs stripe lasers for minimizationof threshold current-application to ridge structures

The gain saturation effect and the various leakage currents related to a strip structure (spreading current, lateral diffusion current, optical cavity recombination current, and Auger recombination current) are considered. The minimum threshold current (3.3 mA) is obtained with a multiquantum-well (MQW) structure (5×80 Å) at a cavity length of 80 μm. At these values, the lateral leakage current (spreading and lateral diffusion currents) represents about 50% of the threshold current. It is shown that for short-cavity lasers, the MQW is preferred to the SQW (single-quantum-well) structure. However, the well number in the active layer of a ridge structure is limited by the decrease of the parallel confinement and the increase of the lateral leakage current. Finally, good agreement was obtained in comparing the calculations with experimental results for GRINSCH (graded-index separate-confinement heterojunction) SQW lasers     

Pulsed and continuous-wave operation of long wavelength infrared(λ=9.3 μm) quantum cascade lasers

The operation of quantum cascade lasers at a wavelength (λ≃9.3 μm) well within the 8-13-μm atmospheric window is reported. A detailed study of intersubband luminescence in a vertical transition structure shows linewidths as narrow as ~10 meV at cryogenic temperatures, increasing to 20 meV at room temperature. Pulsed operation is demonstrated up to 220 K with a peak power ≈10 mW and ≈35 mW at 140 K. The temperature dependence of the threshold current density (J _th) is described by a high T₀ (128 K), J_th is also systematically studied as a function of cavity length to determine the peak gain and waveguide losses. Continuous-wave, single-mode operation is demonstrated up to 30 K with powers ≈2 mW     

Room temperature operation of microdisc lasers with submilliamp threshold current

Electrically pumped whispering-gallery mode microdisc lasers with singlemode operation and submilliamp threshold current at room temperature are demonstrated. The device consists of an InGaAs/InGaAsP multiple quantum well (MQW) structure formed into a 2-10 mu m diameter disc approximately 0.1 mu m thick. These microdiscs are supported on an InP pedestal.<>     

Self-assembling Ge(Si)/Si(100) quantum dots

The morphological evolution of self-assembled epitaxial quantum dots on Si(100) is reviewed. This intensely investigated material system continues to provide fundamental insight guiding the growth of nanostructured electronic materials. Self-assembled quantum dots are faceted, three-dimensional islands which grow atop a planar wetting layer. Pure Ge growth at higher substrate temperatures results in narrower island size distributions but activates additional strain-relief mechanisms which will alter the optical and electronic properties of the dots. Optical and electrical characterization has shown that electrons and holes are confined to different regions of the dot. This results in a spatially indirect, type II recombination mechanism. Emerging device applications which exploit properties of these nanoscale Ge islands are discussed.     

Room temperature λ=1.3 µm photoluminescence from InGaAs quantum dots on (001) Si substrate

GaAs/In_xGa_1−x As quantum dot heterostructures exhibiting high-intensity λ=1.3 μm photoluminescence at room temperature have been grown on (001) Si substrate with a Si_1−x Ge_x buffer layer. The growth was done successively on two MBE machines with sample transfer via the atmosphere. The results obtained by the study of the structure growth process by means of high-energy electron diffraction are presented. __________ Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 36, No. 5, 2002, pp. 565–568. Original Russian Text Copyright ? 2002 by Burbaev, Kazakov, Kurbatov, Rzaev, Tsvetkov, Tsekhosh.     

High-power operation of highly reliable narrow stripe pseudomorphicsingle quantum well lasers emitting at 980 nm

Ridge waveguide pseudomorphic InGaAs/GaAs/AlGaAs single-quantum-well lasers exhibiting record high quantum efficiencies and high output power densities (105 mW per facet from a 6 μm wide stripe) at a lasing wavelength of 980 nm are discussed that were fabricated from a graded index separate confinement heterostructure grown by molecular beam epitaxy. Life testing at an output power of 30 mW per uncoated facet reveals a slow gradual degradation during the initial 500 h of operation after which the operating characteristics of the lasers become stable. The emission wavelength, the high output power, and the fundamental lateral mode operation render these lasers suitable for pumping Er³⁺-doped fiber amplifiers     

Room temperature continuous wave operation of 671 nm wavelengthGaInAsP/AlGaAs VSIS lasers

Room-temperature continuous-wave (CW) operation of a liquid-phase epitaxy (LPE)-grown GaInAsP/AlGaAs laser that uses a V-channel substrate inner stripe (VSIS) structure to obtain current confinement and transverse mode control is discussed. The threshold current and lasing wavelength were 77 mA and 671 nm, respectively, and the temperature dependence of the threshold current was such that the characteristic temperature was 75 K     

High temperature operation of lattice matched and strained InGaAs-InP quantum well lasers

The temperature dependence of lattice matched and strained InGaAs-InP quantum well lasers operating between 1.48 and 1.56 mu m is described. Devices grown under tensile and compressive strain, with an In concentration in the range of 0.43>     

Room temperature 632.7 nm CW operation of AlGaInP strained multiquantum well lasers grown on

Room temperature (25 degrees C) 632.7 nm continuous wave operation of AlGaInP strained multiquantum well lasers has been achieved on     

Room temperature operation of type-II GaAsSb/InGaAs quantum welllaser on GaAs substrates

A GaAsSb/InGaAs type-II quantum well laser diode on GaAs substrates was demonstrated for the first time. Threshold current density of 610 A/cm² was obtained from a 1.1 mm-long broad area laser with the emission wavelength of 1.2 μm     

Room temperature visible (683-713 nm) all-AlGaAs vertical-cavity surface-emitting lasers (VCSELs)

Visible emitting all-AlGaAs vertical-cavity surface-emitting lasers (VCSELs) have been produced by metal organic vapor phase epitaxy (MOVPE) using ultra-high purity source reagents. Lasing was obtained at wavelengths in the range 683-713 nm using four 45 /spl Aring/ Al/sub 0.18/Ga/sub 0.82/As quantum wells in the active region. At room temperature, a minimum threshold current density of 3.8 kA.cm/sup -2/ was measured for a wavelength of 692 nm; this is the lowest value for an all-AlGaAs vertical-cavity laser operating at this wavelength. Growth of the epitaxial mirrors at 5.2 /spl mu/m/h/sup -1/ results in a total growth time of only two and a half hours.     

Room-temperature optically-pumped InGaSb quantum well lasers monolithically grown on Si(100) substrate

Room-temperature optically-pumped In/sub 0.2/Ga/sub 0.8/Sb quantum well lasers on Si are reported. The defect-free monolithic epistructure growth on a Si(100) substrate is initiated by an AlSb quantum dot nucleation layer followed by an AlSb/GaSb superlattice. The 13% mismatch between the AlSb and Si lattice is accommodated by misfit dislocations and associated crystallographic undulations in the AlSb buffer. The nucleation layer and buffer are characterised by atomic force microscopy and transmission electron microscopy. The lasing spectrum is characterised as a function of pump power and polarisation analysis.     

Room temperature operation of GaInAs-GaInAsP-InP SCH multiquantum-film laser with narrow wire-like active region

GaInAs-GaInAsP-InP SCH (separate-confinement heterostructure) multiquantum-film lasers with approximately 100-nm-wide wirelike active regions were fabricated by two-step low-pressure organometallic vapor-phase epitaxy (LP-OMVPE) growth and wet chemical etching and operated at room temperature. An increase in the threshold current density in such lasers was drastically reduced by using a preheating process in hydrogen atmosphere and a thin InP cover layer growth prior to the regrowth of a GaInAsP optical confinement layer. The fabrication processes presented can be very effective for realization of room-temperature operation of long-wavelength quantum-wire and quantum-box lasers based on GaInAs-InP materials.<>     

High-temperature (130 degrees C) CW operation of 1.53 mu m InGaAsP ridge-waveguide lasers using strained quaternary quantum wells

Minimum threshold current density of 0.57 kA/cm/sup 2/ and high T/sub 0/ values up to 74 K were obtained from 400 mu m long broad area lasers with MOVPE grown compressively strained all-quarternary GaInAsP SCH-MQW layer structures for 1.53 mu m emission wavelength. With 3 mu m*400 mu m RW laser diodes (T/sub 0/>90 K) high-temperature CW operation up to 130 degrees C was achieved.<>