Optical gain and photoluminescence as well as radiative and Auger losses are calculated for Ga(AsBi)/GaAs quantum wells. The results are obtained using a consistent microscopic theory and an anticrossing model for the band structure. The influence of the band structure parameters on the optical properties is investigated.

We analyze the modal gain of Ga(NAsP) multi quantum-well heterostructures pseudomorphically grown on (001) silicon substrate by metal-organic vapor-phase epitaxy. Using the variable stripe length method, we obtain high modal gain values up to 78 cm−1 at room temperature that are comparable to the values of common high quality III-V laser material. We find good agreement between experimental results and theoretically calculated gain spectra obtained using a microscopic model. The results underline the high potential of Ga(NAsP) as an active material for directly electrically pumped lasers on silicon substrate.

A detailed microscopic calculation and experimental measurements of the optical gain from a (GaIn)Sb structure are presented. For a given excitation density, the gain in the (GaIn)Sb material system considerably exceeds that of a comparable equivalent (GaIn)As/GaAs structure. The physical reasons for this high gain are analyzed and attributed mostly to band structure effects

Articles you may be interested inOn the measurement of the thermal impedance in vertical-external-cavity surface-emitting lasers Effect of the properties of an intracavity heat spreader on second harmonic generation in vertical-external-cavity surface-emitting laserThe influence of an antireflection coating on the input-output power characteristics and the switch-on dynamics of a vertical-external-cavity surface-emitting laser is investigated numerically with an effective rate-equation simulation based on microscopic many-body calculations for the optical gain/absorption and carrier losses. The simulations show a significantly higher threshold and a slower switch-on dynamics for the antireflection coated devices. These differences are caused by a reduction in the mode amplitude at the position of the active medium due to a less pronounced subcavity.

A series of Ga͑AsSb͒ / GaAs/ ͑AlGa͒As samples with varying GaAs spacer width are studied by electric-field modulated absorption ͑EA͒ and reflectance spectroscopy and modeled using a microscopic theory. The analysis of the Franz-Keldysh oscillations of GaAs capping layer and of the quantum-confined Stark shift of the lowest quantum well ͑QW͒ transitions shows the strong inhomogeneity of the built-in electric field indicating that the field modulation due to an external bias voltage differs significantly for the various regions of the structures. The calculations demonstrate that the line shape of the EA spectra of these samples is extremely sensitive to the value of the small conduction band offset between GaAs and Ga͑AsSb͒ as well as to the magnitude of the internal electric field changes caused by the external voltage modulation in the QW region. The EA spectra of the entire series of samples are modeled by the microscopic theory. The good agreement between experiment and theory allows us to extract the strength of the modulation of the built-in electric field in the QW region and to show that the band alignment between GaAs and Ga͑AsSb͒ is of type II with a conduction band offset of approximately 40 meV.