Room-temperature operation of InAs quantum-dash lasers on InP (001)

The first self-assembled InAs quantum dash lasers grown by molecular beam epitaxy on InP (001) substrates are reported. Pulsed room-temperature operation demonstrates wavelengths from 1.60 to 1.66 μm for one-, three-, and five-stack designs, a threshold current density as low as 410 A/cm² for single-stack uncoated lasers, and a distinctly quantum-wire-like dependence of the threshold current on the laser cavity orientation. The maximal modal gains for lasing in the ground-state with the cavity perpendicular to the dash direction are determined to be 15 cm^-1 for single-stack and 22 cm^-1 for five-stack lasers     

InP(001)衬底上的InAs量子线

在分子束外延生长的InAs/In0.52Al0.48As/InP异质结体系中,形成InAs量子线.这些InAs量子线在生长和结构方面有一些独到的特性,并介绍了本实验室在研究InAs量子线的生长和结构方面所做的工作.     

InAs Wires on InP (001)

在分子束外延生长的InAs/In0.52Al0.48As/InP异质结体系中,形成InAs量子线.这些InAs量子线在生长和结构方面有一些独到的特性,并介绍了本实验室在研究InAs量子线的生长和结构方面所做的工作.     

Room-temperature operation of InP-based InAs quantum dot laser

A ridge waveguide quantum dot (QD) laser with a stripe width of 15 /spl mu/m was fabricated by using the seven-stacked InAs QD layers based on the InAlGaAs-InAlAs material system on InP [001] substrate. Room-temperature lasing operation was observed at 1.501 /spl mu/m, which is the first observation from the InAs QDs with the InAlGaAs-InAlAs structure. The characteristic temperature of the InAs QD laser calculated from the temperature dependence of threshold current density was 135 K in the temperature range from 200 K to room temperature.     

Room-temperature 2.81-/spl mu/m continuous-wave operation of GaInAsSb-AlGaAsSb laser

GaInAsSb-AlGaAsSb multiple quantum-well (QW) lasers with an emission wavelength of 2.81 /spl mu/m are reported. The ridge waveguide lasers with highly strained QWs show continuous-wave laser emission up to 25/spl deg/C; in pulsed mode, the lasers operate up to 60/spl deg/C. For pulsed operation, a threshold current density of 360 A/cm/sup 2/ is found for devices with 30-/spl mu/m stripe width and 2-mm cavity length at room temperature. A low threshold current density at infinite length of 248 A/cm/sup 2/ is derived.     

Room-temperature continuous-wave laser operation of electrically-pumped 1.55 /spl mu/m VECSEL

A report is presented on room-temperature (RT) continuous-wave (CW) laser emission at 1.55 /spl mu/m of an all InP-based electrically-pumped vertical external-cavity surface-emitting laser (EP-VECSEL). Threshold currents of 1.4 kA/cm/sup 2/ and output powers of up to 0.3 mW were measured under CW operation at RT. A maximum output power of 2.7 mW has been obtained in quasi-CW operation at a heatsink temperature of 10.5/spl deg/C. This first result demonstrates that EP-VECSELs are a potential candidate for the realisation of compact vertical-cavity emitting sources.     

Stress evolution aspects during InAs/InP (001) quantum wires self-assembling

We report here in situ measurements of stress evolution during molecular beam epitaxy growth of InAs/InP (001) quantum wires. The obtained results provide the necessary information to understand why quantum wires instead of quantum dots are formed in this heteroepitaxial system: a strong stress anisotropy along 〈110〉 directions is responsible for it. Moreover, during quantum wires growth As/P exchange reactions take place, which determine the total amount of InAs incorporated in the nanostructures and then their optical properties. In situ stress measurements have also been used to study the exchange process and they have allowed us to calculate the quantity of InAs that enters into the lattice because of it.     

Room-temperature, continuous-wave operation for mode-stabilisedAlGaInP visible-light semiconductor laser with a multiquantum-wellactive layer

646 nm continuous-wave operation at room temperature (25°C) has been achieved by a transverse mode stabilised AlGaInP laser diode with a (multi-)quantum-well structure. The laser structure was grown by metalorganic vapour phase epitaxy. The threshold current (density) is 55 mA (4.4 kA/cm²) and maximum light output power is 19 mW. Stable fundamental transverse-mode operation was obtained, at least up to 15 mW     

Room-temperature continuous-wave operation of GaN-based laser diodes grown by raised-pressure metalorganic chemical vapor deposition

We report our new raised-pressure metalorganic chemical vapor deposition (RP-MOCVD) technique and the room-temperature continuous-wave (cw) operation of GaN-based laser diodes grown using this technique. We have found that both the defect density as measured by etch-pit density and optical pumping threshold-powder density decreases as the growth pressure is increased beyond 1 atm. We fabricated GaN-based laser diodes and achieved lasing under cw conditions at 20°C. The threshold current density was 3.5 kA/cm² and the operation voltage at threshold was 16.8 V.     

Room-temperature continuous-wave operation of GaInNAsSb laser diodes at 1.55 /spl mu/m

The first 1.55 /spl mu/m room-temperature continuous-wave (CW) operation of GaAs-based laser diodes utilising GaInNAsSb/GaNAs double quantum well active regions grown by molecular beam epitaxy is reported. In electrically-pumped CW operation the narrow ridge waveguide devices have a room temperature lasing wavelength of 1550 nm near threshold, increasing to 1553 nm at thermal rollover. The CW threshold current was 132 mA for a 3/spl times/589 /spl mu/m device, with a characteristic temperature of 83 K, measured in pulsed mode between 20 and 70/spl deg/C.     

1516nm room temperature CW operation of quantum dot InAs/InP(311)B singlemode laser

Reported is the first demonstration of the performance and properties of a singlemode Fabry-Perot laser processed from InAs/InP(311)B quantum dot material, which gives emission at 1.516 mum under continuous-wave operation at room temperature     

Room-temperature continuous-wave operation of 1.54-μmvertical-cavity lasers

We report on the room-temperature continuous-wave operation of vertical-cavity lasers operating at 1.54 μm. The devices use a 7 strain-compensated quantum-well active layer sandwiched between two Al(Ga)As-GaAs quarter-wave mirrors joined by wafer fusion. Five device sizes between 8 and 20 μm were found to operate continuously at room temperature (23°C), The lowest room-temperature continuous-wave threshold current of 2.3 mA was measured on an 8-μm diameter device, while the highest continuous-wave operating temperature of 33°C was measured on a 12-μm device     

Room-temperature pulsed operation of AlGaAs/GaAs vertical-cavitysurface-emitting laser diode on Si substrate

Room-temperature pulsed AlGaAs/GaAs vertical-cavity surface-emitting laser diode (VCSELD) has been grown on Si substrate using metalorganic chemical vapor deposition. The VCSELD structure grown on Si substrate consists of a single quantum well active layer and a 20-pair of AlAs/GaAs distributed Bragg reflector (DBR). The measured reflectivity of the 20-pair of AlAs/GaAs DBR was 93% at the wavelength of 860 nm. The VCSELD on Si substrate exhibited a threshold current of 79 mA and a threshold current density of 4.9 kA/cm² under pulsed condition at room temperature     

Room-temperature continuous-wave operation of GaN-based blue-violet laser diodes with a lifetime longer than 1000 h

GaN-based continuous-wave operated blue-violet laser diodes (LDs) with long lifetime are demonstrated, which are grown on a c-plane GaN substrate by metal organic chemical vapor deposition with a 10 × 600 μm² ridge waveguide structure. The electrical and optical characteristics of a blue-violet LD are investigated under direct-current injection at room temperature (25 °C). The stimulated emission wavelength and peak optical power of the LD are around 413 nm and over 600 mW, respectively. In addition, the threshold current density and voltage are as small as 1.46 kA/cm² and 4.1 V, respectively. Moreover, the lifetime is longer than 1000 hours under room-temperature continuous-wave operation.     

Long-wavelength strained-layer InAs/GaInAs single-quantum-well laser grown by molecular beam epitaxy on InP substrate

Laser emission is reported for the first time from a 10 monolayer-wide highly strained (3.2%) InAs single quantum well confined by Ga/sub 0.47/In/sub 0.53/As layers. At 80 K the emission spectrum of broad-area laser diodes is centred at 1.836 mu m, the threshold current-density is approximately 500 A/cm/sup 2/ and the characteristic temperature is T/sub 0/ approximately=30 K. CW operation is achieved up to 110 K with narrow-stripe devices but at shorter wavelength, due to increased losses and filling of the quantum-well energy levels.<>     

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.     

Metalorganic vapor phase epitaxial growth and structural characterization of self-assembled InAs nanometer-sized Islands on InP(001)

Self-assembled InAs islands were grown by metalorganic vapor phase epitaxy on InP(001) and characterized by atomic force microscopy and transmission electron microscopy. The growth temperature (450–600°C), the InAs deposition time (3–12 s, using a growth rate of ～2.3Å/s), and the growth interruption time (8–240 s) were varied systematically in order to investigate the effect of thermodynamic and kinetic factors on the structural properties of InAs/InP and InP/InAs/InP structures. It is found that the structural properties of islands vary widely with the growth conditions, ranging from very small (4–5 nm height, ～30–60 nm in diameter) coherent islands at low temperature (450–500°C) to large (～350 nm wide) plastically relaxed islands at high temperature (600°C). For a given deposition time, the height of the coherent islands increases markedly with the growth temperature while their diameter shows only a moderate increase. The growth interruption time also affects the formation and the evolution of islands, which clearly shows that these processes are kinetically limited. Coherent islands with structural properties suitable for use in optoelectronic devices are obtained from ～2.4–4.8 monolayer thick InAs layers using a growth temperature of 500°C and a 30 s interruption time.     

Room-temperature singlemode continuous-wave operation of distributed feedback GaInNAs laser diodes at 1.5 μm

Room-temperature continuous-wave operation of distributed feedback GalnNAs quantum well laser diodes on GaAs in the 1.5 mum wavelength range is demonstrated for the first time. Singlemode emission with a sidemode suppression ratio of more than 45 dB is obtained at 1486 nm with a threshold current of 44 mA and an external efficiency of 0.06 W/A.     

Temperature dependent lasing characteristics of InAs/InP(100) quantum dot laser

We report on the lasing characteristics of InAs/InP(100) quantum dots laser through changing the temperature under continuous-wave mode. Three lasing peaks are simultaneously observed at temperature of 80 K and the lasing order of each peak is unrelated with each other when injection current increases. Laser spectra obtained under fixed current for different temperatures show a drastic influence on their shape. A large spectral broadening is observed at low temperature, while the width of lasing spectra gradually narrows when the operating temperature increased. The lasing process of quantum dot laser is obviously different from that of a reference quantum well laser in the same wavelength region. In addition, very high wavelength stability of 0.088 nm/K in the temperature range of 80–300 K is obtained, which is 6.2 times better than that of reference quantum well laser.     

Chlorine adsorption on the InAs (001) surface

Chlorine adsorption on the In-stabilized InAs(001) surface with ζ-(4 × 2) and β3′-(4 × 2) reconstructions and on the Ga-stabilized GaAs (001)-ζ-(4 × 2) surface has been studied within the electron density functional theory. The equilibrium structural parameters of these reconstructions, surface atom positions, bond lengths in dimers, and their changes upon chlorine adsorption are determined. The electronic characteristics of the clean surface and the surface with adsorbed chlorine are calculated. It is shown that the most energetically favorable positions for chlorine adsorption are top positions over dimerized indium or gallium atoms. The mechanism of chlorine binding with In(Ga)-stabilized surface is explained. The interaction of chlorine atoms with dimerized surface atoms weakens surface atom bonds and controls the initial stage of surface etching.