Sn delta-doping in GaAs

We have prepared a number of GaAs structures S-doped by Sn using the well k nown molecular beam epitaxy growth technique. The samples obtained for a wi de range of Sn doping densities were characterized by magnetotransport expe riments at low temperatures and in high magnetic fields up to 38 T. Hall-ef fect and Shubnikov-de Haas measurements show that the electron densities re ached are higher than for other delta-dopants, like Si and Be. The maximum carrier density determined by the Hall effect equals 8.4 x 10(13) cm(-2). F or all samples several Shubnikov-de Haas frequencies were observed, indicat ing the population of multiple subbands. The depopulation fields of the sub bands were determined by measuring the magnetoresistance with the magnetic field in the plane of the delta-layer. The experimental results are in good agreement with selfconsistent bandstructure calculations. This calculation shows that in the sample with the highest electron density also the conduc tion band at the L point is populated.