Stability of strained MQWs in laser structure

摘要

In this paper, the stability of strained MQWs in laser structure is discussed. The excess stress is the driving force of misfit dislocation multiplication and is a very important factor of strained MQWs stability. So we calculate the excess stress using the single-kink model. Our results show that the maximum position of excess stress is related to the barrier and well thicknesses and mismatches in the well(s). The lattice-matched barriers can dilute the excess stress. The capping layer can also dilute the excess stress in a certain degree. We then calculate the strain relaxation using the dynamic model of dislocations. In this model, the strain relaxation is driven by the excess strains. In this paper, the criteria of the stability of MQWs in laser structure is that the density of dislocations (or the strain relaxation) is less than a certain value. In this way, the barriers and capping layer are both important factors of MQWs stability. The method can be used to better the MQWs in laser structure.