Designing strain-balanced GaN/AlGaN quantum well structures: Application to intersubband devices at 1.3 and 1.55 μm wavelengths

A criterion for strain balancing of wurtzite group-III nitride-based multilayer heterostructures is presented. Single and double strain-balanced GaN/AIGaN quantum well structures are considered with regard to their potential application in optoelectronic devices working at communication wavelengths. The result for realizable, strain-balanced structures are presented in the form of design diagrams that give both the intersubband transition energies and the dipole matrix elements in terms of the structural parameters. The optimal parameters for structures operating at λ∼1.3λ∼1.3 and 1.55 μm were extracted and a basic proposal is given for a three level intersubband laser system emitting at 1.55μm and depopulating via resonant longitudinal optical (LO) phonons (ℏωLO≈90 meV).