Effect of inhomogeneities of Bi2T3 crystals on the transverse Nernst-Ettingshausen effect

The effect of inhomogeneities in p-Bi₂Te₃ crystals, grown by different methods, on the coefficients of the transverse Nernst-Ettingshausen and Hall effects has been studied. The degree of homogeneity of the crystals was estimated on the basis of thermo-emf (Seebeck coefficient) data. It was established that the concentration dependences of the Nernst-Ettingshausen coefficient at T=300 K in homogeneous and inhomogeneous samples are different. This makes it possible to use the Nernst-Ettingshausen effect data for quality assessment of Bi₂Te₃ crystals. It is shown that the anomalous drop of the Hall coefficient with increasing temperature in a number of samples is due to inhomogeneities, and in Sn-doped Bi₂Te₃ crystals it is due to the existence of an impurity level against the background of the valence-band states. Fiz. Tekh. Poluprovodn. 31, 441–443 (April 1997)