Optical Properties of Gallium Arsenide/aluminum Gallium Arsenide and Gallium Aluminum Indium Arsenide/indium Aluminum Arsenide Multiple Quantum Well and Superlattice Structures Grown by Molecular Beam Epitaxy
Gain spectra are characterized as a function of the well-width in GaAs multiple quantum wells with AlGaAs barriers by nanosecond pump-probe spectroscopy. The gain bandwidth is larger for the same peak gain in wider well -width multiple quantum wells and is explained qualitatively. The linewidth broadening factor is calculated from the gain spectra and studied as a material parameter. It is shown that the linewidth broadening factor increases with wavelength and decreases with carrier density. MBE-grown integrated -mirror etalons made from GaAs/AlGaAs, in the 800 nm wavelength region, and GaAlInAs/InAlAs, in the 1.3 mu m wavelength region, exhibit lasing by optical pumping. Below threshold, the 800 nm integrated-mirror etalon is used for nonlinear switching which, in the architecture presented, is capable of extracting a single 10 ps pulse from a pair of pulses spaced 40 ps apart. Nonlinear optical properties of type II GaAs/AlAs short-period superlattices are presented and show an apparent high energy shift of the absorption band edge at 10 K and no shift at 77 K as the absorption is saturated. Type I multiple quantum well structures of similar dimensions show similar high energy band edge shifts for both temperatures, 10 K and 77 K due to phase-space filling. In contrast, electrons in type II structures reside in the barrier and do not contribute to the chemical potential. Transitions in GaAs/AlGaAs coupled-well superlattices show transitions that are a function of the center barrier thickness and reveal shorter carrier lifetimes than a GaAs quantum well of equal thickness without a center barrier.
- Pub Date:
- February 1991
- GALLIUM ALUMINUM INDIUM ARSENIDE/INDIUM ALUMINUM ARSENIDE;
- GALLIUM ARSENIDE/ALUMINUM GALLIUM ARSENIDE;
- Physics: Optics