A complete Raman mapping of phase transitions in Si under indentation

TL;DR

This study provides a comprehensive Raman mapping of phase transitions in silicon under indentation, revealing detailed phase distributions and challenging previous assumptions about amorphous phase localization.

Contribution

It offers the first complete Raman mapping of all silicon phases during indentation, enhancing understanding of phase distribution and material properties.

Findings

Amorphous phase distribution deviates from central localization.

Raman mapping effectively identifies phase regions.

Phase distribution varies with substrate orientation.

Abstract

Crystalline Si substrates are studied for pressure induced phase transformation under indentation at room temperature using Berkovich tip. Raman scattering study is used for the identification of the transformed phases. Raman line as well as area mapping are used for locating the phases in the indented region. Calculation of pressure contours in the indented region is used for understanding the phase distribution. We report here a comprehensive study of all the phases of Si, reported so far, leading to possible understanding of material properties useful for possible electromechanical applications. As a major finding, distribution of amorphous phase in the indented region deviates from the conventional wisdom of being in the central region alone. We present phase mapping results for both Si(100) and Si(111) substrates.