Electrochemical pathway-controlled growth of tellurium nanostructures on a nonconductive substrate

Abstract

This study demonstrates that the morphology and spatial distribution of tellurium (Te) nanostructures can be precisely controlled on electrically insulating substrates (SiO₂) by systematically tuning the electrochemical reaction pathway of HTeO₂⁺. By varying only two key parameters, the precursor concentration and applied potential, the relative contribution of each step, including the overpotential deposition, H₂Te formation, and chemical reduction, was modulated. This enabled the fabrication of diverse nanostructures, including nano-dots, nano-rods, and feather-like morphologies, under different electrochemical conditions. Notably, Te formation was achieved solely via the chemical pathway on insulating SiO₂ without the need for external electron transport, providing the first unambiguous experimental validation of EC-driven formation and growth on electrically insulating substrate. This strategy successfully circumvents the limitations of conventional electroplating techniques, which are generally restricted to conductive substrates, and offers a template-free platform for the site- and shape-selective growth of Te nanostructures. These findings present a promising route toward applications in Te-based sensors, thermoelectric devices, and bio-functional nanomaterials.