HGSE BASED MIXED-CRYSTALS DOPED WITH FE RESONANT DONORS

This article reviews the physical properties of semimagnetic semicondu ctors of the type Hg(1-x-y)Fe(x)A(y)(II)Se(1-z)B(z)(VI) and Hg1-x-yFex MnySe. Optical, magnetooptical, transport and magnetotransport experim ents showed that in Hg1-xFexSe substitutional iron forms a resonant do nor state whose energy is superimposed on the conduction band continuu m. Resulting anomalous properties of electron scattering rate, i.e. st rong enhancement of electron mobility (or drop of Dingle temperature), which occur in Hg1-xFexSe at low temperatures in a certain Fe concent ration range, are described. Next, theoretical models describing this anomalous reduction of the scattering rate are discussed. The descript ion of thermomagnetic, optical, magnetooptical and magnetic properties of Hg1-xFexSe, with emphasis on features originating from the peculia r iron level position in the band structure of Hg1-xFexSe, conclude th e first part of tile present paper. In the second part the physical pr operties of the semiconducting alloys Hg1-xMnxSe:Fe, Hg1-vCdvSe:Fe, Hg 1-xZnxSe:Fe, HgSe1-xTex:Fe and HgSe1-xSx:Fe are described. In particul ar, the dependence of the position of the Fe resonant donor state in t he band structure on the crystal composition is discussed. The values of predicted Gamma(6) and Gamma(8) band, offsets between HgSe and CdSe , HgTe, MnSe and ZnSe are given. The considerable attention is paid to the discussion of the mechanism limiting the electron mobility in the mixed alloys. Finally, topics which have not been explicitly covered in this review are mentioned and open problems are discussed.