Minor switching and RF oscillations in amorphous semiconductors

Abstract

Inherent radio frequency oscillations at 13.7 MHz have been observed in the amorphous semiconductor. As38Te55Ge4Si3 and at 11.4 MHz in 2As2Se3:As2Te3. These oscillations occur at a minor switching event which precedes the major resistive switch. A study of contact effects, ramp excitation and polarity revealed nothing which indicates that the phenomenon is not a property of the material itself. The frequency is independent of loading, pulse repetition rate, and temperature. The threshold for the minor switch is a strong function of temperature. The oscillation may represent the transition from upper localized states to lower extended states. The conductance change would be due to a resulting extension of the recombination free path. If this is the case, a study of the oscillations will yield definitive information concerning the conduction processes in amorphous materials.