The Effect of Crystallinity in HfO2 Thin Films Prepared by Evaporation for 1064 nm Absorption

The optical absorption mechanism and the preparation technology for achieving low absorption of HfO2 thin films at 1064 nm were systematically investigated. Through molecular dynamics simulations and electron density of states calculations, it was determined that oxygen vacancies within the thin films significantly contributed to the absorption of 1064 nm light. HfO2 thin film samples were synthesized using various deposition parameters, followed by comprehensive measurement and analysis of their crystal phase, fluorescence, and microstructure. Theoretical calculations and experimental results indicated that the crystallization of amorphous films increased the presence of oxygen vacancy defects, consequently enhancing film absorption. Notably, following heat treatment at 400 °C, one sample retained a predominantly amorphous structure while exhibiting minimal absorption, suggesting improved optical stability for inertial confinement fusion and industrial laser processing applications.