We present photoluminescence studies of highly excited single self--assembled CdTe quantum dots under continuous--wave and pulsed excitations. We observe appearance of emission bands related to sequential filling of s--, p-- and d--shells. We analyze the inter-shell splitting for five samples, in which the dots were formed from a strained CdTe layer of different width. We find that with increasing the CdTe layer width the inter-shell splitting increases. In a time resolved measurement, we observe a radiative cascade between transitions involving one, two, and more than two excitons.Comment: submitted to Applied Physics Letter

Lamb and shearhorizontal wave production by interdigital transducers deposited on both sides of a piezoelectric plateSurface acoustic waves ͑SAW͒ propagating on the ͑111͒, ͑112͒, and ͑113͒ cuts of gallium arsenide in the ͓110͔ direction are studied both theoretically and experimentally. The possibility of propagation of both normal and leaky surface acoustic waves ͑NSAW and LSAW, respectively͒ is predicted. The acoustoelectrical activity predicted for LSAW is more than 100 times higher than that for NSAW. Three particle displacement components of comparable magnitudes for LSAW propagating on the three cuts are obtained. The lowest attenuation ͑4.94ϫ10 Ϫ5 dB per wavelength͒ is predicted for the LSAW at the ͑112͒, ͓110͔ orientation of GaAs. Theoretical characteristics for the LSAW on the ͑112͒ cut are corroborated experimentally. Experimental values of the phase velocity ͑3.05ϫ10 3 m/s͒, electromechanical coupling coefficient ͑8.1ϫ10 Ϫ4 ͒, attenuation ͑5.7ϫ10 Ϫ3 dB per wavelength͒, and temperature delay coefficient ͑5.2ϫ10 Ϫ5 deg Ϫ1 ͒ are presented. Characteristics of experimental delay lines fabricated on the ͑112͒ cut and the well-known ͑001͒ cut are compared.

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