New ground states of fluorinated and oxidized phosphorene: structural and electronic properties

TL;DR

This study investigates how chemical functionalization with oxygen and fluorine alters the structural and electronic properties of monolayer black phosphorene, revealing tunable bandgaps and anisotropic effective masses for potential electronic applications.

Contribution

It introduces a systematic approach to identify ground states of fluorinated and oxidized phosphorene, highlighting novel properties and controllable electronic characteristics.

Findings

Bandgap varies with adsorbate concentration, switching from direct to indirect.

Chemisorption can rotate the anisotropic effective mass by 90 degrees.

New ground states with unique chemical and electronic properties are identified.

Abstract

We systematically explore chemical functionalization of monolayer black phosphorene via chemisorption of oxygen and fluorine atoms. Using the cluster expansion technique, with vary- ing concentration of the adsorbate, we determine the ground states considering both single- as well as double- side chemisorption, which have novel chemical and electronic properties. The nature of the bandgap depends on the concentration of the adsorbate: for fluorination the direct bandgap first decreases, and then increases while becoming indirect, with increasing fluorination, while for oxidation the bandgap first increases and then decreases, while mostly maintaining its direct nature. Further we find that the unique anisotropic free-carrier effective mass for both the electrons and holes, can be changed and even rotated by 90 degrees, with controlled chemisorption, which can be useful for exploring unusual quantum Hall effect, and novel electronic devices based on phosphorene.