Abstract
Resistivity and Hall effect measurements have been made as a function of both temperature and hydrostatic pressure on a number of different III-V semiconductor materials as well as on structures based on these materials exhibiting two dimensional electron behaviour. These measurements have been used to study the mechanisms by which electrons can be scattered, in fairly high purity GaAs and InP very good agreement between theory and experiment could be achieved using standard models for scattering and an iterative technique for solution of the Boltzmann transport equation. This agreement was found to become progressively worse as the impurity density increased, much improved agreement was obtained considering the correlation in impurity positions frozen into the crystal during growth. Hydrostatic pressure was also used to move a deep level in (AlGa)As through the conduction band edge. By this means resonant electron scattering by the central cell potential of the deep level was observed. Such scattering has been proposed theoretically but to the author's knowledge has not previously been observed experimentally. The scattering rate deduced from the experimental results was found to be in very good agreement with theory Measurements were also made on heterostructures in the (GaIn)As/InP material system at high pressure at room temperature and down to 4K, These measurements demonstrate the contribution that pressure can make to the study of scattering in 2D systems and suggest that current theories of scattering in 2D cannot satisfactorily describe experimental results.