Optoelectronic Properties of (001) and (111) Lattice-Matched and Strained QuantumWire Lasers-Comparison with Quantum Well Lasers

摘要

We investigate the optoelectronic properties of GaAs wires along the 001 and 111directions for a range of cross sections and compare these with the corresponding parameters for optimized quantum wells. The relative benefits of built-in strain in quantum wire and quantum well systems are also studied. We find that the threshold current density in the 100 x 50 A wire is 80 A/sq cm compared with 560 A/sq cm in a 50 A GaAs well. The differential gain in quantum wires is increased by an order of magnitude in comparison with quantum wells, and can be as high as l0 to the -13th sq cm. A narrow gain spectrum is calculated for quantum wire lasers ensuring high mode selectivity and strong damping of relaxation oscillations. We also consider the issue of carrier relaxation in quantum-confined structures, which may impose an upper limit on the laser modulation frequency. Performing a Monte Carlo simulation of the relaxation process, we find that the electron relaxation time in quantum wires is increased to above 100 PS in comparison with 10 ps in quantum wells. (MM).