Influence of barrier height on carrier dynamics in strained ${\mathrm{In}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As/GaAs quantum wells

Strained ${\mathrm{In}}_{\mathit{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As/GaAs heterostructures with different In content x, each containing quantum wells with various well widths ${\mathit{L}}_{\mathit{z}}$ (between 2 and 30 nm) are investigated with use of time-integrated and time-resolved spectroscopy. With increasing temperature, a characteristic drop of both the photoluminescence (PL) intensity and PL lifetime is observed, revealing a strong dependence on In content and well width. The temperature dependencies can be explained by thermal emission of the carriers out of rather shallow quantum wells. The transfer of the carriers between quantum wells of different widths across the GaAs barrier is demonstrated and described by a system of rate equations.