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 enca psulation Czochralski technique is strongly reduced due to mesoscopic elect rical non-uniformities related to the cellular structure of dislocations. A ccording to model calculations using effective medium theory and approximat ing the non-uniformities by a mixture of two different phases (cell walls a nd cell interiors) the most essential inhomogeneity parameters are the rati o 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 differen t influences of both parameters could be separated.