Room temperature optical absorption characteristics of GaAs/AlGaAs multiple quantum well structures under external anisotropic strain

We report the room temperature anisotropic absorption characteristics of a GaAs/AlGaAs multiple quantum well structure under biaxial anisotropic strain that was achieved by bonding to an x-cut LiTaO3 substrate at 150 °C, with the [110] and [1■10] directions of the multiple quantum well along the y and z axes of LiTaO3, respectively. A stronger heavy hole excitonic feature can be observed when the polarization of the incident light is in the compression direction, which thus results in larger quantum confined Stark effect. An absorption coefficient change of 0.6 μm−1 was observed for an applied field of 7.4 V/μm. This change in absorption coefficient is 1.5 times the value obtainable from a multiple quantum well without strain.