Evidence of a two-dimensional to three-dimensional transition in 'SI' 'DELTA'-doped 'GA''AS' structures - Mendonca, C A C; Plentz, F; Oliveira, J. B. B.; Meneses, E A; Scolfaro, L M R; Beliaev, D; Shibli, Suhaila Maluf; Leite, J. R. (Physical Review B, 1993)