SB2TE3 SINGLE-CRYSTALS DOPED WITH CHROMIUM ATOMS

Chromium-doped Sb2Te3 single crystals were prepared from elements of s emiconductor purity using a modified Bridgman method. The samples of t hese crystals were characterized by means of X-ray diffraction analysi s, measurements of the reflectivity in the plasma resonance frequency range omega(P), of the Hall constant R(H) and electrical conductivity sigma. It was found that the incorporation of Cr atoms into the Sb2Te3 crystal lattice reduces the volume of the unit cell, whereas the valu es of omega(P) and R(H) (i.e. the concentration of holes) remain unalt ered and the values of sigma decrease with increasing chromium content . This effect is qualitatively explained by an interaction of incorpor ated Cr atoms with antisite defects of Sb2Te3 crystal lattice. The In (R(H) sigma) VS In T dependences show that the dominant mechanism of s cattering of free charge carriers in the studied crystals is the scatt ering by acoustic phonons; the presence of chromium atoms increases th e scattering rate by ionized impurities.