Electronic–thermal switching and memory in chalcogenide glassy semiconductors

A constant value of the activation energy of direct current conductivity in chalcogenide glassy semiconductors is a strong evidence of the existence of negative-U centers in these materials. Multiphonon tunnel ionization of negative-U centers in strong electric fields is the cause of current–voltage characteristic nonlinearity. Taking into account the Joule heating allows to obtain electronic–thermal instability and then form an S-shaped current–voltage characteristic. The model described in this paper is in good agreement with the available experimental data on chalcogenide glassy semiconductors.