Somephysical properties of Hf-doped-Sb2Te3 single crystals


T.Plechácek1, J. Navrátil1, P. Hájek2,A. Krejcová2, P. Losták2


1Joint Laboratory ofSolid State Chemistry of Institute of Macromolecular Chemistry of the Academyof Sciences of the Czech Republic and University of Pardubice,Studentská 84, 53210 Pardubice, Czech Republic

2Facultyof Chemical Technology, University of Pardubice, Čs. Legií Square565, 532 10 Pardubice, Czech Republic


Single crystals ofHf-doped Sb2Te3 (cHf = 0-2.4x1019cm-3) were prepared from the elements of Sb, Hf and Te of the 5Npurity by a modified Bridgman method. The obtained crystals were characterizedby the measurements of the reflectivity R in the plasma resonance frequencyregion. Values of the plasma resonance frequency, wp, were determined by fitting thereflectance spectra using the relations for the real and imaginary parts of thecomplex dielectric function, following from the Drude-Zener theory. From theobserved changes in the value wp it was concluded that the doping of Hf-atoms into thecrystal structure of Sb2Te3 results in a decrease in theconcentration of free current carriers - holes. This conclusion was confirmedby the measurement of temperature dependencies of the Hall coefficient RH,electrical conductivity s and the Seebeck coefficient a, within the temperature range of 100-400 K.Moreover, temperature dependences of the power factor sa2 and mobility m~(RH.s) of free carriers are discussed.