Exciton localization in In sub (0.53) Ga sub (0.47) As/InP alloy quantum wells.

Spectral holeburning in In sub (0.53) Ga sub (0.47) As/InP alloy quantum wells at low temperatures shows that all heavy- hole excitons within the inhomogenously broadened line are strongly localized by the combination of alloy disorder and interface roughness. Exciton selectively excited within the inhomogeneous line are found to spectrally relax within the line by inelastic scattering off acoustic photons in 16 psec. 

The comparison of inelastic scattering rate (hole recovery time) and homogenous width of the hole (dephasing time) indicates that inelastic scattering dominates leading to a localization length on the order of the exciton size. This is to be compared to GaAs quantum wells where both localized and delocalized excitons were observed. The result shows for the first time the increase in disorder by the alloy composition of InGaAs leads to localization of all exciton states in two-dimensional quantum well structures.