Analysis and probing of surface polarization phenomena in organic films and organic devices

Surface polarization phenomena is discussed in terms of molecular and bioelectronics. Orientational ordering of polar dipoles and displacement of excess electrons at the interface are main origins of surface polarization. Firstly, dielectric polarization phenomena of monolayer comprised of polar molecules are discussed. We show that unique dielectric properties of monolayers is expressed using a set of orientational order parameters, and Maxwell-displacement-current (MDC) measurement coupled with optical second harmonic generation (SHG) measurement is shown as an effective way for detecting surface polarization phenomena of polar monolayers. We then show that dielectric energy stored in monolayers makes a significant contribution to two-dimensional pattern formation. Secondary, dielectric polarization phenomena due to accumulation of electron are discussed in terms of Maxwell-Wagner effect. We show that determination of electric field is essentially important to understand organic device performance. We then show that SHG can probe the electric field distribution in FET channel.