Estimation of carrier density in Te-doped bismuth microwires

Abstract

In this report a new approach to characterizing the carrier density n in Te-doped Bi micro-wires is described. Carrier density is a fundamental parameter for determining the electrical transport

properties of micro- and nanowires to optimize their performance for different applications, such as thermoelectrics. Measurements of the Hall effect, which is basically a 2D phenomenon, may be inapplicable for microwires and the Shubnicov–de Haas (SdH) oscillations for highly doped microwires. To determine the carrier density n of different Te-doped Bi microwires, we used measurements of Seebeck coefficient α(n) at 300 K at relative resistance R300/R4.2(n). Glass-insulated

Bi-Te microwires were prepared by liquid-phase casting by the Ulitovsky method [1]. The samples had a strictly cylindrical shape, the (1011) orientation along the wire axis, a diameter of >0.2 µm, and

a length of a few tens of meters. The From (SdH) oscillations(to 0,4 at %Te) it was estimated Te concentration (in sm-3) at 4.2K. At concentration- 0.3 at %Te there is a sign change thermopover which is a reference point and corresponds Lifshits's to topological transition [2].- to occurrence T- zone of conductivity at alloying.

The results offer practical to optimize these parameters during preparation micro-wires for different applications.