Single-Layered Hittorf's Phosphorus: A Wide-Bandgap High Mobility 2D Material.

Georg Schusteritsch,Chris J Pickard,Martin Uhrin

doi:10.1021/acs.nanolett.5b05068

Abstract

We propose here a two-dimensional material based on a single layer of violet or Hittorf's phosphorus. Using first-principles density functional theory, we find it to be energetically very stable, comparable to other previously proposed single-layered phosphorus structures. It requires only a small energetic cost of approximately 0.04 eV/atom to be created from its bulk structure, Hittorf's phosphorus, or a binding energy of 0.3-0.4 J/m(2) per layer, suggesting the possibility of exfoliation in experiments. We find single-layered Hittorf's phosphorus to be a wide band gap semiconductor with a direct band gap of approximately 2.5 eV, and our calculations show it is expected to have a high and highly anisotropic hole mobility with an upper bound lying between 3000-7000 cm(2) V(-1) s(-1). These combined properties make single-layered Hittorf's phosphorus a very good candidate for future applications in a wide variety of technologies, in particular for high frequency electronics, and optoelectronic devices operating in the low wavelength blue color range.

Highlights

We propose here a two-dimensional material based on a single layer of violet or Hittorf’s phosphorus
Experiments on single-layered black phosphorene have shown mobilities of 286 cm2V−1s−1,10 while using several monolayers have yielded hole mobilities of at least 1000 cm2V−1s−1.11 Though very desirable for many applications and widely studied theoretically and experimentally,[6,7,8] it would be advantageous for many electronics and optoelectronics applications to find a two-dimensional material with a larger, direct, band gap
In this Letter we focus on the single layer form of Hittorf’s phosphorus, which, in allusion to the other Xenes, we suggest calling either monolayer Hittorf’s phosphorus, Hittorf’s phosphorene, or "hittorfene" in order to distinguish it from black phosphorene, which is often just called "phosphorene"

Summary

The elastic moduli along α

Where E is the total energy for compressed/dilated structures, E0 the total energy at equilibrium, and S0 is the equilibrium lattice area in the xy-plane. We show in the same figure the binding energy for n = 1 − 4 layers of black phosphorus, which reaches a much larger value of 0.095 eV/atom (0.083 eV/atom) for PBE+TS (PBE+G06) calculations for black phosphorene (n=1) The latter compares well with the value found using the same van der Waals correction method by Sansone et al (0.084 − 0.089 eV/atom).[34] Since we consider 2-D materials of different thicknesses it is helpful to calculate the binding energy per layer per area, that is the energy to completely separate or exfoliate the bulk into single layers: For hittorfene we find a value of 0.35 J/m2 (0.29 J/m2) for PBE+TS (PBE+G06), smaller than the value for black phosphorene of 0.40 J/m2 (0.35 J/m2) or A7 phosphorene of 0.42 J/m2 (0.41 J/m2).

Hittorf n

Findings

Total DOS s channel p channel