Sidestepping of this problem may be done by means of p-n transition which should result in the compensation of intrinsic carriers [2]. Experimental attempts concerning bulk crystals were reported only for the system Bi-Te-Se up to date. The first work has shown positive to negative transition of Hall coefficient with temperature in the Bridgman solidified Bi₂Te₂Se_0.995 melt [3], while another team has correlated a presence of p- and n- type phases in room-temperature Bi₂Te₂Se crystal with the decay of solid solution [4].

In order to obtain p-n transition in the as-grown crystals of topological insulators it is proposed to use natural segregation of the components during quazi-equilibrium crystallization of solid solution. According to this approach we report the procedure and theoretical explanation of reproducible growth of Bi₂Te₃ single crystals with p- and n- conductivity in the beginning and final parts, correspondingly. Due to orientation of cleavage plane {0001} along the growth axis the samples with p/n junctions were obtained. The electrophysic measurements have shown high charge mobility for this region – more than 6×104 cm²/Vs at Т=4 K.

Also, a possibility of creating p/n transitions in ternary compounds Bi₂(Te,Se)₃ and (Bi,Sb)₂Te₃will be discussed.

Acknowledgments to RFBR project #12-02-00226-a.

References:

1. Zhang H., Liu C.-X., Qi X.-L., Dai X., Fang Z., Zhang S.-C. Topological insulators in Bi₂Se₃, Bi₂Te₃ and Sb₂Te₃ with a single Dirac cone on the surface // Nature Physics 2009, 5, 438-442.

2. J. Wang, X. Chen, B.-F. Zhu, and S.-C. Zhang. Topological p-n junction // Phys. Rev. B 2012, 85, 235131(4).

3. Sh. Jia, H. Ji, E. Climent-Pascual, M.K. Fuccillo, M.E. Charles, J. Xiong, N.P. Ong, R.J. Cava. Low-carrier-concentration crystals of the topological insulator Bi₂Te₂Se // Phys. Rev. B 2011, V.84, 235206(6).

4. J.-Li Mi, M. Bremholm, M. Bianchi, K. Borup, S. Johnsen, M. Sodergaard, D. Guan, R.C. Hatch, P. Hofmann, Bo B. Iversen. Phase separation and bulk p-n transition in single crystals of Bi₂Te₂Se topological insulator // Advanced materials 2013, 25, 889-893.

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