HgSe Based Mixed Crystals Doped with Fe Resonant Donors

Abstract

The article reviews the physical properties of semimagnetic semiconductors of the type Hg1-x-yFexΑ Se1-xΒzVI 1 and Hg1-x-yFexMnySe. Optical, magnetooptical, transport and magnetotransport experiments showed that in Hg1-xFexSe substitutional iron forms a resonant donor state whose energy is superimposed on the conduction band continuum. Resulting anomalous properties of electron scattering rate, i.e. strong enhancement of electron mobility (or drop of Dingle temperature), which occur in Hg1-xFexSe at low temperatures in a certain Fe concentration range, are described. Next, theoretical models describing this anomalous reduction of the scattering rate are discussed. The description of thermomagnetic, optical, magnetooptical and magnetic properties of Hg1-xFe x Se, with emphasis on features originating from the peculiar iron level position in the band structure of Hg 1-xFexSe, conclude the first part of the present paper. In the second part the physical properties of the semiconducting alloys Hg1-x Mn x Se:Fe, Hg1-vCdvSe:Fe, Hg1-xΖnxSe:Fe, HgSe1-xTex:Fe and HgSe1-xSx:Fe are described. In particular, the dependence of the position of the Fe resonant donor state in the band structure on the crystal composition is discussed. The values of predicted Γ6 and Γ8 band offsets between HgSe and CdSe, HgTe, MnSe and ZnSe are given. The considerable attention is paid to the discussion of the m e c h a n i s m l i m i t i n g t h e e l e c t r o n m o b i l i t y i n t h e

Spin interactions in diluted magnetic semiconductors and magnetic semiconductor structures

“…semiconductors in which one can find coexisting magnetic ions of the same chemical nature but different charge states, was discussed in [75]. The DMS with the above property are not at all unusual: the best studied examples are the zero-gap II-VI compounds (HgSe and HgS) with Fe ions for which the 2+/3+ donor level is degenerate with the conduction band (see [76], [77] and the references therein). The different charge states of magnetic ions were also observed in III-V DMS [78][79][80].…”

Properties of Fe Doped β-HgS under Hydrostatic Pressure

“…On the basis of classical and quantum transport measurements it has been suggested that iron in β-ΗgS could create a deep, localized donor state resonant with the conduction band [3,4]. In particular, noticeable effect of low temperature mobility enhancement (well known from the previous investigations of similar II-VI semiconducting system: HgSe doped with Fe -see, e.g., [5]) was found in Hg1-x Fex S samples with the lowest possible Fe concentration (slightly below 2%) [3]. One of the necessary conditions to observe such effect is pinning at the Fermi energy to the resonant donor level and coexistence of empty and occupied donor states.…”