Type-I quantum-well laser diodes with an active region constituted of GaInAsSb-AlGaInAsSb are reported. Broad-area lasers have demonstrated a threshold current density of 255 A/cm2 at room temperature. Distributed-feedback lasers have been operated in the continuous-wave regime at 20°C with a wavelength of 3.06 μm, a threshold current of 54 mA, and an output power of 6 mW.

This paper is dedicated to the fabrication and the characterization of Sb-based electrically-injected RC-LED devices emitting in the mid-infrared wavelength range. These structures operate in Continuous Wave operation at Room Temperature thanks to to a Multi Quantum Well GalnAsSb/AlGaAsSb active region sandwiched between two AlAsSb/GaSb n- and p-doped Bragg mirrors. RC-LED devices with a diameter of 160 mu m were processed and exhibited bright electroluminescence peaked near 2.3 mu m at Room Temperature with an external quantum efficiency of 0.16% at 34 A/cm(2). A wavelength tunability of 0.5 nm/mA was measured. The microcavity enhanced electroluminescence remains narrow over a 50 K temperature range. (c) 2008 Elsevier Ltd. All rights reserved.

In this paper, the process of fabrication of GaSb-based electrically injected resonant-cavity LEDs near 2.3 mu m is detailed. The electrical and optical properties of these diodes operating in continuous wave at room temperature are also presented. The different tested monolithic structures have similar designs with two doped AlAsSb/GaSb Bragg mirrors and an active region with eight GaInAsSb quantum wells. Performances of devices containing or not an n(++) -InAsSb/p(++)-GaSb tunnel junction (TJ) can be compared. The large improvements of electrical resistance as well as output power, observed when a TJ is included, demonstrate all the advantages to use such a technology for the realization of electrically injected vertical cavity structures emitting in the mid-IR on GaSb substrate.

We have made quantum wells laser diodes by Molecular Beam Epitaxy with emission wavelengths from 2.3 mu m to 3.1 mu m. With growing wavelength, threshold current densities increase almost exponentially. We obtained threshold values as low as 65 A/cm(2) at 2.3 mu m and 156 A/cm(2) at 2.62 mu m. At the same time, the valence-band offset decrease from 132 meV (at 2.3 mu m) to 78 meV (at 2.6 mu m). A threshold current density study shows that Auger effect is not the only responsible for the augmentation of J(th). The reduction of internal efficiency eta(i) has a greater impact on the increase of J(th). The diminution of the holes confinement is incriminated for the degradation of eta(i) with growing wavelength. Therefore, to improve J(th) at higher wavelengths another kind of barrier has to be utilized (for example, thanks to the use of the quinary material AlGaInAsSb).

The molecular beam epitaxy growth of A1AsSb/A10.04Ga0.96AsSb distributed Bragg reflectors lattice-matched to InP is studied. The fabrication and characterization of two such reflectors are reported. Fine structural and optical properties of these samples are investigated using double crystal X-ray diffraction, scanning electron microscopy and reflectivity measurements. Main device performances are a 260 nm wide stop-band centred at 1.55 μm with a maximum reflectivity of 90% for the first 8.5 pairs Bragg reflector while the second 15.5 pairs reflector have allowed an improved maximum reflectivity exceeding 96% at 1.6 μm with a stop-band of 220 nm. As a major result, a new type of surface defects is observed on the A1GaAsSb/A1AsSb Bragg reflector surface. Planar and cross-sectional microscopic observation has revealed that defects are initiated from the reflector-substrate interface. The formation of these defects are discussed and it has been related to InAs islands that appear during the in situ InP-substrate oxide desorption procedure.