코히런트한 X-선을 이용한 표면 거동 연구

Surface Dynamics using Coherent X-rays ： X-ray Photon Correlation Spectroscopy

The new method of x-ray photon correlation spectroscopy (XPCS) [1] is developed recently for probing the dynamics of surface height fluctuations as a function of lateral length scale. Measurements were performed on supported polystyrene (PS) films of thicknesses varying from 84 to 333 nm at temperatures above the PS glass transition temperature. Within a range of wave vectors spanning $10^{-3}$ to $10^{-2}$ $nm^{-1}$, good agreement is found between the measured surface dynamics and the theory of overdamped thermal capillary waves on thin films. Quantitatively, the data can be accounted for using the viscosity of bulk PS. (omitted)