Field dependence of drift velocity and electron population in satellite valleys in gallium arsenide

We present, for the first time, simple explicit expressions for the drift velocity and the electron population in the many-valley band structure of n-type gallium arsenide. It is shown that all the experimentally observed features could be well explained if mean-free-path values of 150 nm and 700 nm in the two sets of valleys are assumed. It is indicated that the mobilities of high-mobility valleys are rapidly degraded with the increase in the electric field. The novel results so obtained could be usefully applied in the design and development of semiconducting devices with two or more energy level structures.