Improved carrier transport in intermixed GaAs/AlGaAs laser structure with multi-quantum wells cladding

Abstract

A GaAs/AlGaAs laser structure with multi-quantum-well cladding layer has been employed to investigate the group III interdiffusion. With this structure the photoluminescence (PL) signals from both the top C doped cladding layers and the laser active region quantum wells can be observed simultaneously. In contrast to the depth dependence of the group III vacancy enhanced interdiffusion, the quantum wells in the thick top cladding layer showed a uniform layer intermixing and the extent of intermixing was less than that observed in the quantum wells of the laser active region. The Al-Ga interdiffusion coefficient, DAl-Ga, of the cladding layer is about 4 times less than that of the active region. A more efficient carrier transport from the cladding layer to the active region in the intermixed sample was deduced from the temperature varied PL spectra. The built-in electric field is proposed to enhance the vacancy diffusion in the active region.