Variation Of Carrier Mobility Research Articles

LOW-FIELD MOBILITY OF CARRIERS IN NONDEGENERATE SEMICONDUCTORS

Gunn's theory of the low-field variation of carrier mobility has been extended, using Morgan's analysis to include the effect of scattering by a single optical mode of lattice vibrations. Numerical results obtained for n-germanium show that there is still a serious disagreement between theory and experiment.

The Electrical Conductivity and Thermoelectric Power of Bismuth Telluride

The electrical conductivity and thermoelectric power of the semiconductor Bi2Te3 have been measured between 150°K and 300°K. n-type and p-type samples with a wide range of carrier concentration have been included. Most samples have shown extrinsic conduction and have been partially degenerate over at least part of the temperature range, so it has been necessary to use Fermi-Dirac statistics in interpreting the results. A few samples have exhibited mixed and intrinsic conduction at the higher temperatures. It has been possible to determine the variation of carrier mobility with temperature and to estimate the energy dependence of the relaxation time, as well as a number of the semiconductor parameters.

Preparation and some physical properties of Bi 2Te 3, Sb 2Te 3, and As 2Te 3

The preparation of the intermetallic compounds Bi 2Te 3, Sb 2Te 3, and As 2Te 2 from purified elements by several techniques is discussed. Advantages and disadvantages of the various techniques are enumerated. Electrical and thermal properties are presented as functions of temperature and impurity concentration. The variation of carrier mobility with temperature is approximately T -5 2 for AS 2Te 3 and Bi 2Te 3. An anomalous variation of Hall coefficient with temperature is observed. The thermal conductivities of the three compounds are similar. It is suggested that the compounds are necessarily heavily doped semiconductors because Group-V atoms appear on tellurium lattice sites and tellurium atoms appear on Group-V atom lattice sites.