1:30 PM - 3:30 PM
[16p-P5-14] Surface-Tg Characterization based on Metal-Atom Desorption from Organic Surfaces
Keywords:Glass transition temperature, Surface, Metal-vapor deposition
Interfaces/surfaces are play an important role for a performance of various organic devices. There are no established method so far to measure a surface glass-transition temperature (surface-Tg) within a depth of several nanometers of organic films. We propose a new method for measuring the surface-Tg based on metal-vapor deposition/desorption. Double thickness monitor apparatus, in which one monitor is used in normal usage and another have a quartz oscillator with the organic layer as a substrate, was adopted to monitoring such metal-vapor deposition/desorption characteristics. We found Mg-vapor atoms were not deposited in the initial stage during Mg evaporation but became to deposit after a certain threshold-evaporation time. This threshold time was depending on the substrate temperature (Tsub) and was dramatically increased at Tsub of the several-degree lower than the bulk-Tg. This temperature did not changed for the different deposition rate of Mg and another metal (Pb) deposition. We, therefore, concluded that the temperature refers the surface-Tg.