Crystal structure and epitaxy of Bi2Te3 films grown on Si

TL;DR

This study investigates the crystal structure and epitaxial growth of Bi2Te3 thin films on silicon, revealing high-quality single crystals and the effects of aging on film integrity and substrate interactions.

Contribution

It provides detailed x-ray diffraction analysis of Bi2Te3 films on Si, highlighting epitaxial relationships and aging effects, which were not previously characterized in this context.

Findings

Bi2Te3 films are high-quality single crystals with specific epitaxial relationships to Si.

Aging causes loss of film thickness, interface roughening, and formation of new phases.

Te diffusion into Si substrate alters its structure and composition.

Abstract

We report comprehensive x-ray diffraction studies of the crystal structure and epitaxy of thin films of the topological insulator Bi2Te3 grown on Si (1 1 1). The films are single crystals of high crystalline quality, which strongly depends on that of their substrates, with in-plane epitaxial relationships of Bi2Te3 [2 1 -3 0] || Si [1 -1 0] and Bi2Te3 [0 1 -1 0] || Si [1 1 -2] along which the lattices of 1x3 Bi2Te3 and 2x2 Si supercells are well matched. As the samples age, we observe loss of crystalline Bi2Te3 film thickness accompanied with roughening of the crystalline interfaces, formation of new crystalline phases as well as compositional and structural modification of the Si substrate, consistent with the diffusion of Te into the Si substrate.