The present paper reports the measurements on space
charge limited conduction in amorphous thin films of
Ge20Se$_{80-x}$Agx (x = 0, 10, 15, 20). I−V characteristics have been
measured at various fixed temperatures. These characteristics show that, at
low electric fields, an ohmic behaviour is observed. However, at high
electric fields (E ~ 104 V/cm), the current becomes superohmic.
At high fields (104 V/cm), current could be fitted to the theory of
space charge limited conduction (SCLC) in case of uniform distribution of
localized states in the mobility gap of these materials. Using the theory of
SCLC for the uniform distribution of the traps, the density of localized
states near Fermi level is calculated. It is observed that, on addition of
Ag in Ge20Se80 alloy, density of localized states first increases
till 10 at% of Ag and then decreases.