EVIDENCE OF A 2-DIMENSIONAL TO 3-DIMENSIONAL TRANSITION IN SI DELTA-DOPED GAAS STRUCTURES

We report on the change of character, from an ''isolated'' well to a s uperlattice, of multiple delta-doped structures as a function of the d oping period d(s). This effect is evidenced by the drastic change in t he photoluminescence excitation spectra and the deviation on the total electron density extracted from Shubnikov-de Haas oscillation measure ments as d(s) decreases. Self-consistent-calculation results performed for these systems are used for comparison.