Estimation of the Electron Thermalization Length in Ionic Materials

We report estimations of the thermalization length and the diffusion coefficient of photogenerated carriers in the insulator LiYF₄ as a function of their initial energy. Combining modeling of electron–phonon interaction and the detailed analysis of the kinetic response of fluorescent center Ce³⁺ under vacuum ultraviolet excitation, the thermalization length is obtained as a function of the initial kinetic energy of the electron. This parameter is essential for the description of the carrier recombination in the case of nonideal plasma conditions, where electrons and holes are strongly correlated. This approach also demonstrates the effect of a complicated structure of electronic band on the thermalization process, which impacts the complex nonproportionality response of materials under ionizing radiation excitation