Effect of variation of energy minima separation on Gunn oscillations

The threshold field for Gunn Oscillations depends on the separation in energy of high- and low-mobility conduction-band minima. In GaAs this separation can be reduced by hydrostatic pressure, by uniaxial stress, or by the addition of phosphorus to form GaAs
x
P
1-x
. Experiments on the effect of uniaxial stress are described, and the results are compared with those previously reported for the other two methods of varying the energy separation. Under uniaxial stress the threshold field decreases rapidly with stress along a