THE EFFECT OF HOLE MOBILITY ON ACOUSTIC WAVE AMPLIFIERS.
STANFORD UNIV CALIF MICROWAVE LAB
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Acoustic waves can be amplified by interaction with drifting electrons in piezoelectric semiconductors. Amplifiers built on this principle tend to be unstable, because waves reflected from inhomogeneities or a mismatched output propagate in the backward direction with very little attenuation. It is shown in the present paper that the backward attenuation can be increased substantially by allowing the reflected waves to interact with drifting holes. The propagation characteristics of the waves on the drifting electrons and holes are discussed, and numerical calculations are carried out to show that the presence of the holes-tends to stabilize the amplifier. The proposed scheme requires a piezoelectric semiconductor with high intrinsic conductivity. Author