Instabilities of current in III-V semiconductors

摘要: A description is given of a newly discovered phenomenon which observed when an electric field few thousand V cm-1 applied to homogeneous sample n-type GaAs or InP. Above well-defined threshold field, time-dependent decrease in current observed, largely independent external circuite conditions. In long specimens this aperiodic, resembling random noise with bandwidth ∼ 109 c/sec. short specimens, coherent oscillations are whose period equal the transit time electrons between ohmic electrodes structure. Frequencies over range 0.5--6.5 Gc/sec have been generated way, using experimental techniques described. Measurements efficiency dc-to-rf conversion (from 1 2%), and peak power outputs (up 0.5 W), suggest that new effect may useful applications. Some diagnostic experiments described results discussed terms various possible mechanisms. Although quantitative agreement theory poor it concluded instability possibly be due amplification lattice optical modes.