TIME-RESOLVED DFWM, EXCITE PROBE AND TRANSIENT GRATING STUDIES OF INXGA1-XAS GAAS SUPERLATTICES

Low-temperature time-resolved degenerate four-wave mixing (DFWM), sing le-beam excite/probe and transient grating measurements have been perf ormed on InxGa1-xAs/GaAs superlattices with thin (approximately 6 nm) InxGa1-xAs wells. We find weak dephasing of heavy-hole (hh) excitons b y acoustic phonons. The hh exciton homogeneous linewidth temperature c oefficient is 1.9 +/- 1 mueV K-1. The low-temperature hh exciton optic al nonlinearity is successfully modelled in terms of exciton phase-spa ce filling and exchange interactions in the hh exciton gas. From low-t emperature transient grating measurements we find hh exciton in-plane mobilities as high as 6.7 x 10(4) cm2 V-1 s-1 and mobilities which are greater in superlattices with thinner barriers.