Strong excitation intensity dependence of the photoluminescence line shape in GaAs_1-xBi_x single quantum well samples, Y.I. Mazur, V.G. Dorogan, M. Schmidbauer, G.G. Tarasov, S.R. Johnson, X. Lu, M.E. Ware, S-Q. Yu, T. Tiedje, G.J. Salamo, J. Appl. Phys. 113, 144308 (2013)

A set of high quality single quantum well samples of GaAs_1-xBi_x with bismuth concentrations not exceeding 6% and well widths ranging from 7.5 to 13 nm grown by molecular beam epitaxy on a GaAs substrate at low temperature is studied by means of photoluminescence (PL). It is shown that the PL line shape changes when the exciton reduced mass behavior changes from an anomalous increase (x < 5%) to a conventional decrease (x > 5%). Strongly non-monotonous PL bandwidth dependence on the excitation intensity is revealed and interpreted in terms of optically unresolved contributions from the saturable emission of bound free excitons.