EXCITON ABSORPTION BLEACHING STUDIES IN ORDERED GAXIN1-XP

Using time-resolved small-signal exciton absorption bleaching at low t emperature as a spectroscopic technique, the optical transition energi es from all three valence bands in spontaneously ordered GaxIn1-xP hav e been measured with high accuracy. The origin of the bleaching signal and the contributions of reflection, strain, and binding energy are d iscussed. With three measured energies from each sample, all parameter s in the quasicubic perturbation model can be fitted. Good agreement i s obtained with a spin-orbit-splitting parameter of 103 meV, nearly in dependent of the degree of ordering. The ratio of band-gap reduction t o crystal-field-splitting parameter is found to be 2.7, slightly highe r than previous works. This difference is attributed to a more accurat e determination of light-hole-like band-gap energy.