Conductivity of Se _(95)As _5 chalcogenide glassy semiconductor layers containing the EuF _3 rare-earth impurity in high electric fields

摘要

By investigating the I-V characteristics of an Al-Se _(95)As _5:EuF _3-Te structure, it is established that, upon the application of a positive potential to Te, the current flows in it by the mechanism of space-charge-limited currents (SCLCs) of unipolar-injection, and the N-type I-V characteristic is observed for the opposite polarity. It is shown that these are processes of the thermal-field ionization of neutral and negatively charged U - centers, which play a dominant role in the current-flow mechanism in the investigated structures upon the application of an electric field with intensities exceeding 10 ~5 V/cm. These are also processes of the electron-hole recombination and capture of charge carriers at U - centers. The energy position and concentration of the local states, which correspond to the indicated centers and characterize the effect of the electric field-activation length are determined. It is established that it is the EuF _3 impurities that predominantly affect the local-state concentration.