Hot-electron noise in two-valley semiconductors: An analytic model.

We present results for the hot-electron noise in two-valley semiconductors, such as GaAs, where intervalley transfer plays an important role. The noise is calculated by a Boltzmann —Green-function method. We obtain an analytic solution for a model with two valleys and three relaxation times. Using the measured low-field mobility, lower-valley mass, and valley separation energy 6, while adjusting three upper-valley parameters, we obtain good agreement with both experimental time-of-flight measurements and microwave noise measurements. We find that the hot-electron noise is very sensi-