The sub-terahertz region absorption of sputter deposited nanoscale TiAlV thin films

Abstract

Absorption in the sub-terahertz region in TiAlV thin films with their potential usage in detectors and plasmonic applications is a crucial point for device performance. This work aims to investigate the thickness-dependent evolution of the sub-terahertz region absorption, electrical resistivity in TiAlV thin films deposited by DC magnetron sputtering and to study the structure-property correlation. For structural analyses, X-ray diffraction and transmission electron microscopy techniques have been used. In different deposition conditions, TiAlV thin films indicating the β-Ti phase with anisotropic growth and the hexagonal AlTi3 phase with equiaxial growth have been produced. High resistivity values have been measured in films with the AlTi3 phase. In all TiAlV thin films with different structures, thickness dependent resistivity change in the range 3–23 nm, whereby a strong increase in electrical resistivity with decreasing film thickness have been observed below a thickness of 6 nm. The sub-terahertz absorption increases with increasing film thickness. The highest terahertz region absorption has been found for the films with the β-Ti phase and anisotropic growth also indicating higher electrical conductivity, which favors absorption sensitive applications in the terahertz region. © 2022 Elsevier B.V.