MONTE-CARLO STUDIES ON THE WELL-WIDTH DEPENDENCE OF CARRIER CAPTURE TIME IN GRADED-INDEX SEPARATE-CONFINEMENT HETEROSTRUCTURE QUANTUM-WELL LASER STRUCTURES

The total carrier capture time and the quantum well width are both important parameters affecting the graded-index separate confinement heterostructure (GRINSCH) quantum well laser modulation speed limit. However, discrepancies exist in the literature on the well-width dependence of the carrier capture times. To study this phenomenon, we have developed a Monte Carlo technique to simulate carrier relaxation in GRINSCH quantum well structures. Our results show that the carrier capture time increases with the density of carrier injection. Furthermore, depending on the concentration of injected carriers, the capture time will either decrease, remain the same, or increase with increases in the well width. At lasing conditions, the times are more or less independent of the well width up to 100 angstrom. We compare our calculations to published experiments and find good agreements.