Thermoelectric properties of Bi2Te3 microwires

We present here a study of electrical and thermoelectric properties of n- and p-Bi2Te2, microwires (n-type Bi2Te2Se, p-type Bi0.5Sb1.5Te3) with different diabmeters (d=10-20 mu m). Cylimdncal Bi2Te3 crystals with glass coating were prepared by the liquid phase casting were prepared by the liquid phase casting in a glass capillary. The X-ray studies have shown that the microwire core is in general polycrystal consistring of big disoriented single crystal blocks. Measurements of resistance and thermopower were carried out over a wide range of temperatures (4.2-300 K) and magnetic fields (0-14 T) At 300 for samples of n- and p-type the thermpower s and power factor P.f = S-3 sigma were (100-40) mu V/K 16x10(3) W/(K(2)m) and (150-300) mu V/K4.5x10(-3) W/( K(2)m). respectively. Magnetic field dependences or l'oN er !actor ere measured at vmous temperatures (T=35, 100. 270 K) and different magnetic field orientations. A broad Ma the dominant reaturc or the magnetic held dependence or power !actor 1br p-type samples while power factor decreases for n-typc samples. We have obtained inaimuin pov\ en factor P.f:=0.8 10 K/K(2)m for p-type sample at longitudinal magnetic held B=3 at 7=100 K. Shubmkov de Ilaas oscillations \\ ith equal periods.Delta B=0.038.T-1 both in longitudinal and transverse magnetic fields Con carriers with in, 0.15m(0) in p-type Bi2Te3 microwire were observed. these oscillations could arise rrom the topological surface states.