Temperature dependence of the conductivity of tellurium whiskers

A comparative analysis of the electrical conductivity of whisker, epitaxial film, and single crystal of tellurium was undertaken in the 77–273 K temperature range. The electrical conductivity of the film and single crystal increases monotonically up to 200 K, after which it begins to rise steeply, corresponding to the thermal excitation of intrinsic carriers. The electrical conductivity of whiskers decreases with increasing temperature to 230 K, after which it begins to increase more gradually. It is assumed that in the case of tellurium whiskers, the classical size effect takes place: the decrease in electrical conductivity is due to diffuse scattering of carriers by the lateral surface of the crystal of tellurium and is intensified with increasing temperature. The uneven, tightly-convoluted surface of developed samples is shown in images produced in a scanning electron microscope in the nanometer range.