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The energy level structure of a step-like GalnNAsSb/GaAsN/GaAs quantum well (QW) by photoreflectance was investigated. The incorporation of Sb atoms into GalnNAs alloy helps to achieve QW structures, which emit light at longer wavelength and have quite narrow emission line and small Stokes shift.

Optical properties of the as-grown and annealed GaN0.027As0.863Sb0.11/GaAs single quantum wells (SQWs) were investigated by photoluminescence (PL) and photoreflectance (PR) spectroscopies. It was shown that the annealing produces a considerable improvement of the optical properties of GaN0.027As0.863Sb0.11/GaAs SQW, the enhancement of the PL intensity and a reduction of defect-related PL band.

We analyze the temperature sensitivity of 1.5-μm GaInNAsSb lasers grown on GaAs. Building on the method of Tansu and coworkers, we find evidence that the characteristic temperatures for the threshold current T0 and external efficiency T1 are balanced by a combination of monomolecular recombination and temperature destabilizing mechanism(s) near room temperature. At elevated temperatures, the destabilizing process(es) dominate, due to increased threshold current density Jth. While it is difficult to definitively identify carrier leakage, Auger recombination, or a combination of the two as the responsible mechanism(s), results indicate that carrier leakage certainly plays a role. Evidence of intervalence band absorption was also found; T1 was reduced, but Jth and T0 were not significantly degraded. Conclusions are corroborated by supporting measurements of the Z-parameter with bias, spontaneous emission spectrum, and band-offsets. Spontaneous emission measurements show evidence of weak Fermi-level pinning within the active region at threshold, indicating a form of carrier leakage. This is consistent with the characteristic temperature analysis and a leakage mechanism is proposed. This process is partially responsible for the greater temperature sensitivity of device parameters and the poor internal efficiency. Methods for reducing the effects of each parasitic mechanism are also described. [ABSTRACT FROM PUBLISHER]

Lasing at 1.460 µm from a monolithic, GaInNAsSb vertical cavity surface emitting laser (VCSEL), the longest wavelength on GaAs to date, is demonstrated. Threshold current was 0.58 A (17 kA/cm²), pulsed with a duty cycle of 0.1%. The VCSEL was cooled to reach threshold, from 700 mA at 0°C to 580 mA at -10°C. [ABSTRACT FROM AUTHOR]

Low-threshold room temperature continuous wave 1.49 μm GaInNAsSb lasers are presented. Room temperature threshold current density of 1.1 kA/cm[SUP2] was observed with a high external quantum efficiency of 40% and maximum output power of 30 mW from both facets. [ABSTRACT FROM AUTHOR]

Abstract: Optical properties of a Ga0.62In0.38As0.954N0.026Sb0.02/GaAs single quantum well (SQW) tailored at ∼1.5μm have been investigated by photoreflectance (PR) spectroscopy. The identification of the optical transitions was carried out in accordance with theoretical calculations, which were performed within the framework of the usual envelope function approximation. Using this method, four confined states for both electrons and heavy holes have been found and the optical transitions between them have been determined. The obtained result corresponds to a conduction band offset ratio close to 80%. In addition, the effect of ex situ annealing has been investigated. Lineshape analysis of the PR transitions shows that one of the phenomena responsible for the blueshift of QW transitions is the change in the nitrogen nearest-neighbour environment from Ga-rich to In-rich environments. [Copyright &y& Elsevier]