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International audience; This article reports the improvement of broad area lasers epitaxially grown on InP(311)B substrate. Thanks to optimized growth techniques, a high density of uniformly sized InAs quantum dots (QDs) up to 10 11 cm-2 is obtained. The device, which contains only two stacks of QDs, exhibits a ground state laser emission at 1.54 µm at room temperature associated with a threshold current density as low as 170 A/cm2. Experimental results also demonstrate a modal gain greater than 8 cm-1 per QD plane.

Theoretical and experimental studies of the electronic properties of InAs(Sb) quantum dots (QDs) grown on InP substrate are presented. Unstrained bulk InAsSb present direct gap between 0.1 eV to 0.35 eV suitable for mid infrared emitters (2-5 µm). However, strain and quantum confinement effects may limit the extension of the emission spectrum of these nanostructures towards the longer wavelengths. Various combinations of barrier materials are considered in the simulations. Photoluminescence (PL) spectroscopy experiments on molecular beam epitaxy (MBE) grown samples show promising results. We obtained PL peak beyond 2 µm at room temperature (RT) with InAs/InGaAsP/InP(100) QDs High arsine flow rate during the growth of the QDs makes possible this long emission wavelength. Two ways are investigated to incorporate antimony in InAs/InGaAs/InP(100) nanostructures: growth interrupt of InAs QDs under Sb flux and direct growth of InAs(Sb). A red-shift of the PL peak from 1.85 µm to 2 µm is observed in the first case whereas emission wavelengths as long as 2.35 µm are observed in second case.

A theoretical and experimental study of the electronic properties of InAsSb quantum dots (QDs) grown on InP substrate is presented. Unstrained bulk InAsSb presents a direct gap between 0.1 eV to 0.35 eV, suitable for mid infrared emitters (3–5 µm). However, strain and quantum confinement effects may limit the extension of the emission spectrum of these nanostructures towards longer wavelengths. Various combinations of barrier materials are considered in the simulations. First photoluminescence spectroscopy experiments on molecular beam epitaxy (MBE) grown samples show promising results. Triple stacks of InAs QDs embedded in a GaInAsP alloy lattice matched to InP and grown by the Stranski-Krastanov mode exhibit room temperature (RT) luminescence at about 2 µm. Emission wavelengths as long as 2.35 µm have been observed at RT in a InAsSb/InGaAs/InP structure. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The MBE growth of In/sub 0.52/Ga/sub 0.18/Al/sub 0.30/As ( lambda /sub g/=1.06 mu m) layers in the temperature range of 400-450 degrees C was demonstrated to give high-quality optical waveguides which not only exhibit low propagation losses as low as 0.5 dB/cm at lambda =1.55 mu m but concomitantly high resistivity of >10/sup 4/ Omega cm. The refractive index of In/sub 0.52/Ga/sub 0.18/Al/sub 0.30/As was estimated to be 3.207+or-0.03 at lambda =1.55 mu m.

A two‐wavelengths transmission method is presented for measuring the thickness of epitaxial layers with a resolution of better than 10 nm. The measuring speed is high which for the first time makes possible an imagelike presentation of thickness inhomogeneities in layers. A calibration scheme is described which allows quantitative thickness measurements. By the example of measuring buried layers inside a heterostructure the versatile use of the method is demonstrated.

A pair of GaInAs photodiodes was integrated to the output waveguides of an optical Y-branch. Light was butt coupled to the photodetective zone which was formed by GaInAs LPE growth refilling deep etched holes. Total light conversion with more than 90% internal quantum efficiency at 1.55 mu m wavelength was achieved. The best diodes exhibited dark currents of 1 nA at -10 V bias voltage.