OBSERVATION OF LOW-FREQUENCY ELECTRICAL-CURRENT OSCILLATIONS IN FERROCENE SAMPLE WITH ADSORBED 2-PROPANOL VAPOR

Low-frequency oscillations in electrical current (dark) as a function of time were observed, in the temperature range where unusual/anomalou s change in electrical conductivity with temperature was noticed in th e samples of ferrocene with physically adsorbed 2-propanol vapor (at 4 0 torr pressure) molecules as impurities in a sandwich type of cell co nfiguration. With the increasing bias voltage across the electrodes, a t a constant sample cell temperature, increase in both the time interv al between the two consecutive current peaks (i.e. decrease in frequen cy of current oscillations) and current peak height was noticed. The c urrent-voltage characteristics behavior of ferrocene with adsorbed 2-p ropanol vapor has indicated the ohmic nature of conductivity. Existing theories of current oscillations in semiconductors have failed to exp lain the observed low-frequency current oscillations in this organomet allic semiconductor. Such current oscillations are possibly associated with some kind of time dependent phase changes in the ferrocene- (2-p ropanol) vapor system/surface layer. (C) 1997 Elsevier Science Ltd.