Two-dimensional modeling of the self-limiting oxidation in silicon and tungsten nanowires

Abstract

h i g h l i g h t s• A new diffusion-controlled kinetic model for nanowire oxidation is developed. • A finite reactive region is included to account for oxidation stress and suboxide formation.• Self-limiting nanowire oxidation and its curvature/temperature dependence are predicted. • Results are consistent with observed oxidation behavior of silicon (Si) and tungsten (W) nanowires. a b s t r a c tSelf-limiting oxidation of nanowires has been previously described as a reaction-or diffusion-controlled process. In this letter, the concept of finite reactive region is introduced into a diffusion-controlled model, based upon which a two-dimensional cylindrical kinetics model is developed for the oxidation of silicon nanowires and is extended for tungsten. In the model, diffusivity is affected by the expansive oxidation reaction induced stress. The dependency of the oxidation upon curvature and temperature is modeled. Good agreement between the model predictions and available experimental data is obtained. The developed model serves to quantify the oxidation in two-dimensional nanostructures and is expected to facilitate their fabrication via thermal oxidation techniques.

A Scalable Method for Thickness and Lateral Engineering of 2D Materials

“…For instance, while so far we have considered only the substitution of two oxygen atoms, oxidation might in fact proceed through the formation of substoichiometric oxides − and the self-limiting process observed for GeS 2 and GeAs but not for GeS could be related to a larger strain occurring in the former cases with respect to the latter (see Supporting Information Note 2). The presence of a largely strained interface has been indeed invoked to explain the self-limiting oxidation of silicon nanostructures. − At this regard, we suggest that ab initio molecular dynamics simulations, which will be the focus of future investigation, could provide more satisfactory answers on the presence of substoichiometric oxides as well as on the role of kinetic and thermal effects.…”

Significant Propagation Loss Reduction on Silicon High-Mesa Waveguides Using Thermal Oxidation Technique

“…Finally, This work applied dry thermal oxidation at 1000 ℃ from 1 to 4 hours (hrs) under the gas condition as O2:N2=1:4 (mole ratio). The propagation loss α was evaluated by using Fabry-Perot interferometric method [14]. Light from a distributed feedback laser source was coupled into the waveguide in TE mode through a polarization-maintaining lensed fiber.…”

Nanosilicon-Based Composites for (Bio)sensing Applications: Current Status, Advantages, and Perspectives

“…Traditionally, this nanomaterial can be fabricated from bulk Si by RIE [44] and MACE [45] in combination with lithographic techniques (photolithography, polystyrene nanosphere lithography) or bottom-up and top-down technologies [46]. In addition, the initial synthesis of SiNWs is often accompanied by thermal oxidation steps to yield structures with an accurately tailored size and morphology [47].…”