Molecular Beam Epitaxy

19MBE Growth, Magnetic and Magneto‐optical Properties of II–VI DMSs

Shinji Kuroda

Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki, 305‐8573, Japan

19.1 II–VI DMSs Doped with Mn

Diluted magnetic semiconductors (DMSs) or semimagnetic semiconductors are mixed crystals in which a fraction of the constituent elements of the host semiconductor are randomly replaced by a magnetic element of transition‐metal (TM) or rare‐earth (RE) element possessing an intrinsic magnetic moment. The history of DMSs dates back to studies in the late 1970s on II–VI compounds doped with Mn, expressed as (A^II,Mn)B^VI (Figure 19.1) [1,2]. These mixed crystals have attracted much attention, particularly due to their peculiar magneto‐optical effect arising from the interaction between carriers in semiconductors and localized magnetic moments of Mn d‐electrons [ 1, 2].

Figure 19.1 Bandgap energy E_g vs. lattice constant a of various II–VI DMSs in which Mn is incorporated in sulfide, selenide, and tellurides. Solid lines represent that the mixed crystals A^II_1−xMn_xB^VI in this range of Mn content x can be synthesized using non‐thermal equilibrium growth methods such as MBE.

The molecular beam epitaxy (MBE) growth of II–VI DMSs was first reported in Mn‐doped II–VI DMSs such as Cd_1−xMn_xTe [3] and Zn_1−xMn_xSe [4]. The growth of these ternary compounds can be realized by just supplying a Mn flux in addition ...