Identifying structural order in Selenium with Near-Edge Spectroscopy

TL;DR

This study uses synchrotron X-ray spectroscopy to analyze the structural order in selenium and arsenic-selenium alloys, revealing that amorphous selenium resembles disordered helical chains similar to the trigonal crystalline phase.

Contribution

It provides new insights into the atomic structure of amorphous selenium and arsenic-selenium alloys using advanced spectroscopy techniques.

Findings

Amorphous selenium is composed of disordered helical chains.

The structure is closer to trigonal crystalline phase than monoclinic.

Crystalline order correlates with features in XANES spectra.

Abstract

We investigate the crystallization of amorphous arsenic-selenium alloys with 0%, 0.5%, 2%, 6%, 10%, and 19% arsenic by atomic concentration using synchrotron X-ray absorption spectroscopy. We identify crystalline order using the extended X-ray absorption fine structure (EXAFS) spectra and correlate this order to changes in features of the X-ray absorption near edge structure (XANES) spectra. We find supporting evidence that the structure of amorphous selenium is composed of disordered helical chains, and is therefore closer to the trigonal crystalline phase than the monoclinic crystalline phase.