Abstract

Restriction of carrier wave functions in semiconductor structures of reduced dimensionality results in increased oscillator strength in the excitonic absorption which can be exploited in the design of novel nonlinear optical devices[1]. We report transient bleaching studies of CdSe "quantum dots" whose size is small relative to the bulk material exciton radius. Subpicosecond hole burning and steady-state luminescence spectroscopies are used to characterize the spectral dynamics and isolate the single particle spectrum of these 45 Å diameter CdSe microcrystallites. These clusters, which are grown by a new synthetic method,[2], have well developed wurtzite crystal structure,[3], high quantum yield of band edge luminescence, low saturation intensities, (≈100µJ/cm²) and long bleaching recovery times. Our measurements were performed at 25K in dilute glasses.

© 1990 Optical Society of America