Midinfrared electroluminescence in quantum cascade structures with InP/InGaAs active regions

We report on the midinfrared emission from electroluminescent devices with quantum cascade active regions based on InGaAs/InP heterostructures. We observe emission at lambdasimilar to12 mum from two different structures and compare their emission characteristics based on the different band structure designs. Their relevance in view of the realization of InP-based quantum cascade lasers with aluminum-free waveguides is discussed.