Effects of AlGaAs cladding layers on the luminescence of GaAs/GaAs_(1-x)Bi_x/GaAs heterostructures

摘要

The structural and optical properties of GaAs_(1-x_Bi_x quantum wells (QWs) symmetrically clad by GaAs barriers with and without additional confining AlGaAs layers are studied. It is shown that a GaAs/GaAs_(1-x)Bi_x/GaAs QW with x~4% and well width of ~4 nm grown by molecular beam epitaxy demonstrates efficient photoluminescence (PL) that becomes significantly more thermally stable when a cladding AlGaAs layer is added to the QW structure. The PL behavior for temperatures between 10 and 300 K and for excitation intensities varying by seven orders of magnitude can be well described in terms of the dynamics of excitons including carrier capture in the QW layer, thermal emission and diffusion into the cladding barriers. Understanding the role of these processes in the luminescence of dilute GaAs_(1-x_Bi_x QW structures facilitates the creation of highly efficient devices with reduced thermal sensitivity and low threshold current.