GRADED QUANTUM-WELL STRUCTURES MADE OF DILUTED MAGNETIC SEMICONDUCTORS

In this paper we review results of studies of two types of spatially g raded quantum well structures containing various layers of diluted mag netic semiconductors Cd1-xMnxTe or Cd1-x-yMnxMgyTe. The design of the structures has been recently proposed by us and suitable samples have been grown by a modified molecular beam epitaxy method. In the structu res of the first type a digital profiling of the composition of the co nstituent material in the growth direction allowed to produce quantum wells with a specifically required shape of the confining potential (i ncluding parabolic, half-parabolic, triangular, and trapezoidal). Such samples were used for (i) determination of the conduction and valence band offsets in MnTe/CdTe and MgTe/CdTe systems, (ii) for the demonst ration of an enhanced exciton binding in a parabolic confining potenti al as well as for (iii) demonstration of the possibility of ''spin-spl itting engineering'' in diluted magnetic semiconductors quantum struct ures. In the second type of the structures, a precise in-plane profili ng of either quantum well width or the barrier width or n-type doping intensity was realized. These structures were subsequently used for st udies of the evolution of optical spectra with an increase in the conc entration of confined two-dimensional gas of conduction electrons. PAC S numbers: 73.20.Dx, 78.55.Et.