Mobility degradation and transferred electron effect in gallium arsenide and indium gallium arsenide

The effect of mobility degradation on the intervalley transfer of electrons in gallium arsenide and indium gallium arsenide is studied. A considerable degradation of the mobility at high electric fields takes place for valleys with high low-field ohmic mobility. The momentum relaxation time τ = m^*µ/e is found to degrade with high electric field, giving the impression of high collision broadening at high electric fields. Similar degradation is expected for the mean free path. The relationship of the high-field transport in terms of ohmic transport parameters is elaborated to explain the transferred electron effect.