Thick Epsilon-Near-Zero ITO Metamaterial Films

ε- and μ-near-zero (EMNZ) metamaterial has been demonstrated for unconventional tailoring and manipulation of the light-matter interaction. Therefore, it provides a platform for new optoelectronic devices having desirable properties and functionalities. In this paper, we studied several ITO films with different thickness and annealing process to explore the possibility to develop a host EMNZ metamaterial for a new type of optoelectronic devices that is environmental insensitive. We have characterized these ITO films with ellispsometry study, X-ray diffraction, TEM and SIMS, etc. The results indicated that a thicker self-assembled annealed ITO film has a no uniform permittivity (ε) which varies from a negative to a positive value from the substrate to the top surface. In order to make the ITO metamaterial useful, we studied the method to produce a thicker than 1.5μm ITO with ε-near-zero (ENZ) and slight negative condition. The goal is to develop an ENZ metamaterial process that is compatible for Si-based integrated optoelectronic platform.