Differential Thickness Layer Resistance Measurement method for measurements of contact resistance of organic semiconductor thin films

摘要

The objective, basic theory and application of a new DTLRM (Differential Thickness Layer Resistance Measurement) method of contact resistance R-c (resistance of interface) and contact resistivity measurements are described. The method was developed for ultrathin films of high-ohmic organic semiconductors. The method is based on measurements of total resistance R-T,R-1, R-T,R-2 between two opposite planar contacts on two samples of differing thickness L-1, L-2 prepared from the same organic semiconductor. The important requirements are that both the opposite contacts are ohmic, that linear dimensions of the contacts are much larger than the film thickness, and that the actual measured data are consistent in the sense of condition 1 < R-T,R-2/R-T,R-1 < L-2/L-1. The DTLRM method was verified on zinc phthalocyanine samples with Au and Pt contacts. If the basic assumptions are fulfilled, the DTLRM method can be applied to a broad range of high-ohmic thin films. (C) 2015 Elsevier Ltd. All rights reserved.