Silver Oxide Hexagonal Micromeshes Grown on Amorphous Silicon Designed as Subterahertz Waveguides

Abstract

Herein, silver oxide (Ag2O) hexagonal micromeshes grown onto amorphous silicon (a-Si) thin films are employed as millimeter-wave guides suitable for highfrequency applications. The hexagonal micromeshes and a-Si films are deposited using the physical evaporation technique in a vacuum media. Structural and morphological studies indicated the growth of the hexagonal phase of Ag2O. The observed grains formed a hexagonal meshed network that extends for more than 300 μm, with each hexagon exhibiting a diameter of ≈8.0 μm. Impedance spectroscopy analyses of these waveguides have demonstrated their ability to exhibit a negative capacitance (NC) effect in the frequency range of 0.01– 1.44 GHz. The waveguides display both positive and negative cutoff frequencies reaching beyond 100 GHz at a carrier frequency of 1.44 GHz. In addition, the Ag2O waveguides function as band-pass/reject filters, displaying a minimum reflection coefficient of 0.013, a maximum return loss of 37.5 dB, and a minimum voltage standing wave ratio (VSWR) of 1.04. The features of the waveguides based on hexagonal micromeshes—including the NC effect, high cutoff frequency reaching subterahertz ranges, high return loss, and low VSWR—nominate these devices for applications, such as noise reduction, signal amplification, frequency stabilization, and 6G communications