Abstract

The relaxation of photoexcited carriers in InGaP bulk and in InGaP-lnAlP multiple quantum wells (MQW) structures grown by gas-source molecular beam epitaxy has been studied using the subpicosecond pumpprobe absorption technique. The samples had a molar concentration of indium x = 0.49. The bulk sample consisted of a 400-nm-thick InGaP layer cladded between InAlP layers to minimize carrier recombination due to surface states. The MQW structure was composed of 30 periods of 6.4-nm INGaP wells separated by 22-nm. InAlP barriers. Both samples were etched to remove the GaAs substrate and then were attached to a glass slide as self-standing films for optical analysis. The 0.2-ps pump-probe optical pulses were produced by a linear-cavity dual-jet dye laser with internal group velocity dispersion compensation, which was excited by a frequency- doubled mode-locked Nd-YLF laser.

© 1992 Optical Society of America