An investigation into the effects of thermal annealing on long wavelength InGaAs/InGaAsP multi-quantum well lasers

Multi-quantum well (MQW) inter-mixing was achieved through a set of controlled thermal anneals and were performed on a range of strained and unstrained InGaAs/InGaAsP MQW systems to establish the role of strain in the interdiffusion process. The exposure to high temperatures, as is the case in many fabrication and growth processes, can cause the inter-diffusion of both group V and III species throughout the MQW region. The variation in compositional concentration from the as-grown regime causes lattice mismatch, and thus strain, at the heterostructure interfaces. This intermixing alters the material structure and can affect device performance. The investigation was extended to assess the effects of MQW inter-mixing on the performance of 1.5μm lasers. Room temperature photoluminescence analysis was used in the characterization of the inter-mixing process and results are presented