Phosphorus Pentamers: Floating Nanoflowers form a 2D Network

TL;DR

This paper reports the discovery of a new 2D phosphorus layer composed of floating pentamers forming a network with semiconducting properties, characterized by STM, STS, and DFT, highlighting its potential for electronic applications.

Contribution

It introduces a novel polymorphic 2D phosphorus structure made of floating pentamers, characterized by experimental and theoretical methods, expanding the landscape of 2D materials.

Findings

Identified a new 2D phosphorus polymorph with pentamer units

Demonstrated semiconducting behavior with a 1.20 eV band gap

Showed the formation of homogeneous domains at low temperature

Abstract

We present an experimental investigation of a new polymorphic 2D single layer of phosphorus on Ag(111). The atomically-resolved scanning tunneling microscopy (STM) images show a new 2D material composed of freely-floating phosphorus pentamers organized into a 2D layer, where the pentamers are aligned in close-packed rows. The scanning tunneling spectroscopy (STS) measurements reveal a semiconducting character with a band gap of 1.20 eV. This work presents the formation at low temperature (LT) of a new polymorphic 2D phosphorus layer composed of a floating 2D pentamer structure. The smooth curved terrace edges and a lack of any clear crystallographic orientation with respect to the Ag(111) substrate at room temperature indicates a smooth potential energy surface that is reminiscent of a liquid-like growth phase. This is confirmed by density functional theory (DFT) calculations that find a small energy barrier of only 0.17 eV to surface diffusion of the pentamers (see Supplemental Material). The formation of extended, homogeneous domains is a key ingredient to opening a new avenue to integrate this new 2D material into electronic devices.