Characterization of an AlGaAs/GaAs asymmetric triangular quantum well grown by a digital alloy approximation

An asymmetric triangular quantum well was grown by molecular-beam epitaxy using a digital alloy composition grading method. A high-resolution electron micrograph (HREM), a computational model, and room-temperature photoluminescence were used to extract the spatial compositional dependence of the quantum well. The HREM micrograph intensity profile was used to determine the shape of the quantum well. A Fourier series method for solving the BenDaniel–Duke Hamiltonian [D. J. BenDaniel and C. B. Duke, Phys. Rev. 152, 683 (1966)] was then used to calculate the bound energy states within the envelope function scheme for the measured well shape. These calculations were compared to the E11h, E11l, and E22l transitions in the room-temperature photoluminescence and provided a self-consistent compositional profile for the quantum well. A comparison of energy levels with a linearly graded well is also presented.