High electrical conductivity in out of plane direction of electrodeposited Bi₂Te₃ films

The out of plane electrical conductivity of highly anisotropic Bi₂Te₃ films grown via electro-deposition process was determined using four probe current-voltage measurements performed on 4.6 - 7.2 μm thickness Bi₂Te₃ mesa structures with 80 - 120 μm diameters sandwiched between metallic film electrodes. A three-dimensional finite element model was used to predict the electric field distribution in the measured structures and take into account the non-uniform distribution of the current in the electrodes in the vicinity of the probes. The finite-element modeling shows that significant errors could arise in the measured film electrical conductivity if simpler one-dimensional models are employed. A high electrical conductivity of (3.2 ± 0.4) · 10⁵ S/m is reported along the out of plane direction for Bi₂Te₃ films highly oriented in the [1 1 0] direction.