First-Principles Investigation of Morphological Evolution of Tungsten Growth on Alumina Surfaces: Implications for Thin-Film Growth

Abstract

The fundamentals and interfacial interaction mechanism of tungsten-alumina heterostructures are not yet fully understood. Here, we present a first-principles investigation of the thermodynamic driving force responsible for the phase transition from amorphous to crystalline in the growth of a tungsten thin film on an alumina substrate. Density functional theory and ab initio molecular dynamics collectively provide a first-principles explan-ation of how amorphous tungsten films become thermodynami-cally favorable at finite nanoscales (0.7 nm). The growth of cubic tungsten films is energetically inhibited until the thickness exceeds 0.7 nm. An amorphous tungsten layer would therefore sustain conformal coverage below such a thickness. The approach described here can be applied to computational discovery and design of corrosion-resistant materials, alloys, and semiconductors, providing an ab initio framework to search for methods of optimizing both conductivity and interfacial adhesion. Other possible applications include the synthesis of energy-storage materials, solid-state batteries, and thin-film growth of semiconductor materials, particularly for the prediction of pathways for choosing polymorphs during growth.