Unencapsulated Czochralski growth normal to the c axis was used to produce good quality Bi2Te3 single crystals. Growth was successful both in H2 and in an inert atmosphere with a seed rotation speed of 30 rpm and a pull rate of 12 mm/h. Residual acceptor concentration for nominally stoichiometric crystals was about 1019 carriers cm-3. The distribution constant for Te is 10-2 so that with large Te excesses in the liquid and slow growth rates, n-type (1019) material could be prepared. Doping with Ti, Cr, Mn, Fe, Co, Ni, Ge and Sn was studied. Mn has a distribution constant of 10-1 so that samples with as much as 0.3% Mn could be prepared. The normal freeze equation was not obeyed probably because of facet effects and changes in melt stoichiometry as freezing proceeds. The relative ease of growth and doping suggests that single crystal growth and characterization of other nontetrahedral semiconductors could be worthwhile and that bismuth telluride could be an interesting host for the study of magnetic ions in semiconductor single crystals.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Inorganic Chemistry
- Materials Chemistry