Enhanced ultra high frequency EMI shielding with controlled ITO nano-branch width via different tin material types

The development of technologies for electromagnetic wave contamination has garnered attention. Among the various electromagnetic wave frequencies, for high frequencies such as those in the K and K_a ranges, there is a limitation of using only the properties of a single material. Therefore, it is necessary to improve the absorption coefficients by increasing the path of electromagnetic waves through internal scattering at an interface or a structure inside the material. Here, we accurately demonstrated the role of Sn in the growth of an indium tin oxide (ITO) nano-branch structure and grew high-density ITO nano-branches with the lowest thickness possible. Consequently, we obtained shielding efficiencies of 21.09 dB (K band) and 17.81 dB (K_a band) for a film with a thickness of 0.00364 mm. Owing to the significantly high specific shielding efficiency and low thickness and weight, it is expected to be applied in various fields.