ON THE DETERMINATION OF SOME ELECTRICAL CONDUCTION PARAMETERS OF GaAs-n BY MAGNETORESISTANCE MEASUREMENTS

The geometrical magnetoresistance is presented as a means of determining conduction parameters for high mobility semiconductors. The measurements have been made on the bulk-grown GaAs-n 'sandwich'structures and on Gunn diodes without magnetic cap.The magnetoresistance mobility has been determined by measuring the variation of active layer resistance in a low magnetic field perpendicular to the electric field direction. For this purpose the metal-semiconductor contact resistance, determined from the structure resistance vs.magnetic field intensity and the angle between the magnetic field and the electric field, has been used. In order to determine the scattering coefficient, the Hall mobility has been determined by using the van der Paw method .The resistivity has been obtained from the active layer resistance and the sample geometry. The concentration of charge carriers has been determined from resistivity and the Hall mobility. The charge carrier mobility has been found in the small area covered by the contact.