Parameters of mesoscopic non-uniformities and their influence on the Hall mobility in undoped high-resistivity LEC GaAs
The Hall mobility in undoped high-resistivity GaAs grown by the liquid encapsulation Czochralski technique is strongly reduced due to mesoscopic electrical non-uniformities related to the cellular structure of dislocations. According to model calculations using effective medium theory and approximating the non-uniformities by a mixture of two different phases (cell walls and cell interiors) the most essential inhomogeneity parameters are the ratio of the carrier concentrations and the ratio of the volumes of both phases. Comparing the calculated dependences of the Hall mobility on the carrier concentration and on the temperature with experimental results the different influences of both parameters could be separated.