Direct evaluation of the hopping rate in Langmuir multilayer assemblies

Abstract

Conductivity dispersion has been observed in the heterogeneous assemblies of Cd-palmitate and Cd-arachidate monolayers prepared using the Langmuir-Blodgett technique. The transition rate of hopping carriers in Cd-palmitate monolayers has been directly evaluated from the dispersion frequency by applying the theory presented in the previous paper. The rate values agree with those calculated for Cd-palmitate employing the corrected layer thickness allowing for a finite thickness of interface layers. Comparison with the theoretical predictions has confirmed the validity of the single-rate scheme with nearest-neighbor approximation as an appropriate model to describe the actual system. The results indicate, however, the inadequacy of the evaluation of effective carrier concentration based on a two-dimensional degenerate electron system adopted in the earlier works, whereas the values of other parameters agree in order of magnitude with those estimated before.