Conductivity of layers of a chalcogenide glassy semiconductor Ge2Sb2Te5 in high electric fields

Effect of high electric fields on the conductivity of 0.5-1-A mu m-thick layers of a chalcogenide glassy semiconductor with a composition Ge2Sb2Te5, used in phase memory cells, has been studied. It was found that two dependences are observed in high fields: dependence of the current I on the voltage U, of the type I ae U (n) , with the exponent (n a parts per thousand 2) related to space-charge-limited currents, and a dependence of the conductivity sigma on the field strength F of the type sigma = sigma(0)exp(F/F (0)) (where F (0) = 6 x 10(4) V cm(-1)), caused by ionization of localized states. A mobility of 10(-3)-10(-2) cm(2) V-1 s(-1) was determined from the space-charge-limited currents.