Conformal, Conducting Poly(3,4-ethylenedioxythiophene) Thin Films Deposited Using Bromine as the Oxidant in a Completely Dry Oxidative Chemical Vapor Deposition Process

Poly(3,4-ethylenedioxythiophene) (PEDOT) thin films were obtained through oxidative chemical vapor deposition (oCVD) by using a new oxidant—bromine. The use of bromine eliminates any post processing rinsing step required with other oxidants like iron chloride and hence makes the process completely dry. Film properties are further compared with the PEDOT films deposited using iron chloride as the oxidant. Accelerated aging experiments show longer retention of electrical conductivity for the PEDOT films obtained using bromine as the oxidant. Conductivities as high as 380 S/cm were obtained for PEDOT films deposited using bromine as the oxidant at 80 °C, which is significantly higher than that for PEDOT films deposited using iron chloride as the oxidant at the same temperature. Cross-sectional SEM of the PEDOT films deposited using bromine on silicon trench wafers demonstrates high conformal deposition of the films. All the results show the possibility of depositing highly conducting, conformal PEDOT films on any substrate including silicon, glass, paper, and plastic.