Bansal, Bhavtosh and Hayne, M and Arora, B A and Moshchalkov, Victor V. (2007) Magnetic field-dependent photoluminescence linewidths as a probe of disorder length scales in quantum wells. Applied Physics Letters, 91 (25). ISSN 1077-3118
Photoluminescence from highly disordered GaAs quantum wells is studied in magnetic fields up to 50 T. The monotonic decrease of the photoluminescence linewidth with increasing quantum well thickness indicates that interface roughness is the primary source of line broadening. The magnetic field-dependent exciton linewidth shows an unexpected behavior. We observe not only just a monotonic increase in linewidth but also a field-dependent decreasing linewidth in thicker quantum wells. These observations are understood by postulating the existence of two correlation lengths for the interface fluctuations, one much smaller than the exciton size and the other one of the order of the exciton size.
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