Method for the simultaneous determination of vertical and horizontal mobilities in superlattices.

A magnetoresistance method is proposed which extracts both the growth direction mobility and the planar mobility of an anisotropic thin film, such as a superlattice. A magnetic field which varies in magnitude and orientation is employed. Errors appearing in previous magnetotransport studies on superlattices are resolved. In particular, it is shown that the contact layers used to send currents through an active region do not have a negligible resistance, even if they are much more conductive than the active region. The technique is demonstrated on an InAs/GaSb-based structure where the growth axis to planar mobility anisotropy ratio is found to drop rapidly with increasing temperature. [ABSTRACT FROM AUTHOR]