Two-dimensional MgP3 monolayer with remarkably tunable bandgap and enhanced visible-light and UV optical absorptions

doi:10.1016/j.physe.2021.114960

Physica E: Low-dimensional Systems and Nanostructures

Volume 135, January 2022, 114960

https://doi.org/10.1016/j.physe.2021.114960 Get rights and content

Highlights

•
The MgP₃ monolayer is identified as a new member of the XP₃ monolayer family.
•
The bandgap can be controlled from 0.32 to 1.35 eV under −8%-8% biaxial strain.
•
2%–4% tensile strain can significantly increase the visible light and UV absorption.
•
The biaxial strain over 6% makes the direct bandgap become an indirect one.
•
Present carrier mobilities are larger than those of several reported XP₃ monolayers.

Abstract

Two-dimensional (2D) monolayered magnesium triphosphides (MgP₃) is identified as a new member of the 2D XP₃ family. Interestingly, a strain less than 8% can induce the bandgap of the MgP₃ monolayer changing in a large range from 0.32 to 1.35 eV. On the basis of the first-principles calculations, the geometrical structure of the newfound MgP₃ monolayer is relaxed, and the dynamical/thermal stabilities are assured by carrying out calculations of phonon dispersion and ab initio molecular dynamics simulation, respectively. The HSE06 calculations give a direct bandgap of 1.18 eV and enhanced visible-light and UV optical absorptions for the MgP₃ monolayer with strain-free. The carrier mobility is higher than those of the several previously reported XP₃ monolayers and demonstrates a significant difference between the electron and the hole carrier mobilities. Strain engineering can significantly affect both the bandgap and optical absorption. These findings indicate that the MgP₃ monolayer could have potential applications of optoelectronic, photovoltaic, and photocatalytic materials or devices.

Graphical abstract

Introduction

Two-dimensional (2D) materials have received extensive attention since the discovery of graphene due to their unique properties and huge promising applications [[1], [2], [3]]. 2D materials have been reported with many remarkable properties, for example, high carrier mobility, large specific surface area, and insulating topology [4]. For example, the 2D phosphorus has an adjustable bandgap under strain engineering [5]. Additionally, the phosphorene monolayer demonstrates several novel electronic properties [[6], [7], [8], [9], [10]] containing the satisfactory bandgap of 1.51 eV and the high hole mobility close to 2.6 × 10⁴ cm²V⁻¹s⁻¹ [10]. The self-assembled monolayers(SAM) have been widely used in field-effect transistors [11]. For example, the field-effect transistor has been successfully manufactured with few-layer black phosphorus [9,[12], [13], [14]], and the hole mobility is as high as 5.2 × 10³ cm²V⁻¹s⁻¹ while the drain current modulation can reach 10⁵ [9,14]. The potential applications of monolayer materials in the photovoltaic fields were also reported. In 2018, Haq et al. [15] investigated the different phases of SnSe and found that the single-layer honeycomb polymorphs SnSe is very suitable for photovoltaic applications. Recently, Ali et al. [16] have summarized the SAM's applications in the interface engineering of perovskite solar cells to enhance stability and efficiency. Lei et al. [17] discovered a new PdSe₂ monolayer with anisotropic and large carrier mobility could be used as a photovoltaic material. The narrow bandgap monolayer and SAM can also be used as thermoelectric materials. Park et al. [18] made a comprehensive review on the SAM's thermal conductance. In fact, many investigations for the thermoelectric properties of monolayers are reported recently. For example, the potential thermoelectric applications of lead-chalcogenide monolayers at room temperature are explored by Haq et al. [19] 2D materials can have a wide range of applications in the fields of electronics and optical devices. Therefore, the electronic and optical properties of 2D materials have been studied extensively. For example, Singh et al. [20] reported the optical and electronic properties of ThO₂, UO_2, and PuO₂. Singh et al. [21] and Bhuyan et al. [22] studied the optical and electronic properties of several monolayers.

Recently, a series of studies on the properties of 2D triphosphides have been carried out, and many interesting results have been reported. In 2017, the 2D GeP₃ monolayer is reported by Jing et al. [23]. The largest carrier mobility of the monolayer is 8.84 × 10³ cm² V⁻¹ s^−1, and the optical absorption in the visible-light range is apparent. Lu et al. [24] found that the CaP₃ monolayer with a direct bandgap of 1.15 eV and ultrahigh carrier mobility. Very recently, the BiP₃ [25] and AlP₃ [26] monolayers are found to be excellent electronic and optical properties, and they can be used as potential photocatalysts for hydrogen evolution reaction under strains. Therefore, XP₃ monolayers have become a monolayer family with various novel optoelectronic properties.

In this paper, inspired by the discovery of 2D CaP₃ monolayer by Lu et al. [24], we suggest a triphosphate monolayer of MgP₃ with the P1 space group as a new part of the XP₃ monolayer family. The geometrical structure of the MgP₃ monolayer is constructed and relaxed according to that of the CaP₃ monolayer, and the stability is confirmed by the phonon dispersion with density functional perturbation theory and the structural and energy evolutions with ab initio molecular dynamics simulation(AIMD). By utilizing the first-principles density functional theory(DFT) with hybrid functional(HSE06) [27,28], we investigate the electronic and optical properties. The results show that the MgP₃ monolayer possesses a direct 1.18 eV bandgap and can be remarkably changed by strain engineering. Meanwhile, the apparent optical absorption in ultra-violet(UV) and visible light range and anisotropic carrier mobilities are also observed. The strain engineering can apparently impact the conduction band edge, the bandgap value, and the optical absorption. The remarkably tunable bandgap and enhanced visible and UV light absorption imply that the MgP₃ monolayer could be used as a promising candidate for photovoltaic, solar energy harvesting, and optoelectronic devices or materials.

Section snippets

Computational method

The electronic properties are calculated by employing the DFT method with plane-wave basis sets, which is completed with the Vienna ab initio simulation package (VASP 6.1.2) code [29,30]. In the geometrical optimization, the generalized gradient approximation based on the Perdew–Burke–Ernzerh of parameterization (PBE) is taken up to describe the electron interactions with exchange-correlation functional [27]. The electronic properties and optical absorption are obtained with the aid of the

Geometry and stability of the MgP₃ monolayer

The fully optimized geometrical structure of the MgP₃ monolayer with the P1 space group is shown in Fig. 1. The lattice parameters a and b are 5.59 and 5.71 Å, respectively. In the primitive cell, the red balls are Mg atoms and the blue ones are P atoms. The Mg atoms are six coordinated (six Mg–P bonds), there are two types of P atoms, one type is four coordinated (four P–P bonds), and the other type is four coordinated (two P–P bonds and two Mg–P bonds). As shown in Fig. S1, there is a small

Conclusion

The geometrical structure of the MgP₃ monolayer with the P1 space group is identified on the basis of the first-principles calculations. The dynamical and the thermal stabilities of the newfound monolayer have been assured by employing the phonon dispersion and the AIMD simulation. The electronic properties, carrier mobility, and optical properties of the MgP₃ monolayer are obtained with HSE06. A direct bandgap of 1.18 eV is identified for the newfound monolayer, and the carrier mobility of the

Author statement

Miao Liu: Data curation, Investigation, Writing-Original draft preparation. Chuan-Lu Yang: Conceptualization, Methodology, Supervision, Writing-Reviewing and Editing. Mei-Shan Wang: Visualization. Xiao-Guang Ma: Software.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

This work was supported by the National Natural Science Foundation of China (NSFC) under Grant Nos. NSFC-11874192.

References (64)

S. Singh et al.
J. Nucel Mater.
(2018)
P.D. Bhuyan et al.
Superlattice. Microst.
(2019)
H.Y. Liu et al.
Appl. Surf. Sci.
(2020)
R.N. Somaiya et al.
Superlattice. Microst.
(2021)
L.B. Zhan et al.
Physica. E
(2020)
H. Ahmad et al.
Renew. Sustain. Energy Rev.
(2015)
A.H. Reshak
J. Catal.
(2017)
Z. Mahdavifar et al.
J. Alloys Compd.
(2021)
P. Li et al.
Opt Commun.
(2013)
H.C. Huang et al.
Renew. Energy
(2018)

Y.L. Li et al.

Int. J. Hydrogen Energy

(2017)

R.N. Somaiya et al.

Superlattice. Microst.

(2021)

K.S. Novoselov et al.

Science

(2004)

M.J. Allen et al.

Chem. Rev.

(2010)

C.N.R. Rao et al.

Angew. Chem. Int. Ed.

(2009)

S.Z. Butler et al.

ACS Nano

(2013)

H. Guo et al.

J. Phys. Chem. C

(2014)

S. Zhang et al.

Angew. Chem.

(2016)

R. Fei et al.

Nano Lett.

(2014)

S.P. Koenig et al.

Appl. Phys. Lett.

(2014)

L. Li et al.

Nat. Nanotechnol.

(2014)

J. Qiao et al.

Nat. Commun.

(2014)

H. Chen et al.

Small

(2019)

H. Liu et al.

ACS Nano

(2014)

M. Buscema et al.

Nano Lett.

(2014)

G. Long et al.

Nano Lett.

(2016)

B.U. Haq et al.

Phys. Rev. B

(2018)

F. Ali et al.

Adv. Energy Mater.

(2020)

W. Lei et al.

J. Mater. Chem. C

(2019)

S. Park et al.

J. Mater. Chem.

(2020)

B.UI. Haq et al.

Ceram. Int.

(2021)

D. Singh et al.

J. Mater. Sci.

(2018)

Cited by (33)

Direct Z-scheme β-SnSe/HfS<inf>2</inf> heterostructure for photocatalytic water splitting: High solar-to-hydrogen efficiency and excellent carrier mobility
2024, Materials Today Communications
Constructing directly stacked Z-scheme van der Waals (vdW) heterostructures of different two-dimensional (2D) monolayers is one effective approach to developing highly efficient photocatalysts. In this study, a β-SnSe/HfS₂ heterostructure is designed, and its electronic properties and photocatalytic water splitting performance are systematically investigated through first-principles calculations. The charge density difference and work function indicate the presence of an electric field within the heterostructure, further demonstrating its characteristic direct Z-scheme heterostructure. The heterostructure exhibits excellent photocatalytic activity with higher light absorption coefficients of up to 6.67 × 10⁵ cm⁻¹ in the visible and ultraviolet regions compared to the two monolayers alone. The heterostructure possesses high electron mobility in the x direction (2405.86 cm²s⁻¹V⁻¹) and high hole mobility in the y direction (537.56 cm²s⁻¹V⁻¹), facilitating the separation of electron-hole pairs. According to Gibbs free energy, the heterostructure can split water spontaneously overall in acidic settings and only needs an extra potential of 0.64 eV to do so in neutral situations. It is anticipated that the heterostructure have a solar-to-hydrogen (STH) efficiency of up to 14.29%. Because of this, the β-SnSe/HfS₂ heterostructure possesses a significant amount of promise for use as a photocatalyst in the generation of hydrogen through the process of water splitting.
Sc<inf>2</inf>CCl<inf>2</inf>/WX<inf>2</inf> (X = Se, Te) van der Waals heterostructures for photocatalytic hydrogen and oxygen evolutions with direct Z-schemes
2023, International Journal of Hydrogen Energy
The Sc₂CCl₂/WSe₂ and Sc₂CCl₂/WTe₂ heterostructures are identified for efficient photocatalytic overall water splitting with direct Z-schemes, although the conduct band minimum for the Sc₂CCl₂ monolayer and the valence band maximums of the WSe₂ and WTe₂ ones do not match the redox potential conditions. The photocatalytic direct Z-schemes are constructed for the two heterostructures according to the built-in electric fields and band alignments. The solar-to-hydrogen efficiency $η_{S T H}$ , together with the Gibbs free energies are evaluated to understand the photocatalytic activities and feasibilities. The maximum $η_{S T H}$ can reach 20.70% with the Sc₂CCl₂/WTe₂ heterostructure and higher than 7.35% with the Sc₂CCl₂/WSe₂ one. Interestingly, the biaxial tensile strains remarkably boost the $η_{S T H}$ of the Sc₂CCl₂/WSe₂ heterostructure but weakly impact that of the Sc₂CCl₂/WTe₂ one, while the compressive strains substantially reduce the $η_{S T H}$ of the Sc₂CCl₂/WSe₂ heterostructure but raise that of the Sc₂CCl₂/WTe₂ one. Moreover, the Gibbs free energies indicate the considered hydrogen and oxygen evolution reactions have thermodynamic feasibilities.
Design and characterization of novel 2D TlPt<inf>2</inf>X<inf>3</inf> (X = S, Se, Te) semiconductor monolayers for electronic and optoelectronic applications
2023, Materials Today Communications
The energy crisis and environmental issues have stimulated an increasing interest in developing novel materials, such as two-dimensional (2D) materials, with customized photocatalytic and photovoltaic features for sustainable energy production. In this study, we thoroughly investigated the stability, physical characteristics, electronic properties, optical behaviors, and photocatalytic potential of TlPt₂X₃ (X = S, Se, Te) monolayers (MLs) using state-of-the-art density functional theory calculations at HSE06 and PBE-GGA levels of theory. Our calculations show that these MLs are dynamically, thermally, mechanically, and thermodynamically stable. The elastic constant calculations indicate that these MLs possess high mechanical flexibility owing to their small Young's modulus. The HSE06 approach calculations reveal that the TlPt₂S₃, TlPt₂Se₃, and TlPt₂Te₃ MLs possess band gaps of 1.364 eV (indirect), 1.896 eV (indirect), and 1.174 eV (direct), respectively. The optical characteristics of these MLs demonstrate a wide absorption spectrum that can be activated by visible light, with considerable absorption intensity in the near ultraviolet range. Our findings demonstrate that the TlPt₂Se₃ (TlPt₂Te₃) ML exhibits remarkable hydrogen-oxygen (oxygen) evolution performance with an increase (decrease) in pH value, suggesting they can be used for photocatalytic water splitting under visible light. These results provide new directions for the use of these materials in photocatalytic water splitting and optical devices.
Tuning electronic properties of Z-scheme InSe/HfS<inf>2</inf> heterostructure by external electric field and biaxial strain
2023, Materials Science in Semiconductor Processing
In this investigation, the photoelectric properties of InSe/HfS₂ van der Waals heterostructure (vdwH) are investigated based on the first-principles calculations. The results show that the lowest −0.59 eV binding energy and the 0.67 eV indirect bandgap are achieved at a layer spacing of 3.31 Å, the type-II band alignment and Z-scheme charge transfer mechanism are more favorable for collection and separation photogenerated carriers. Further calculations show that the electronic structure and of the heterostructure can be regularly adjusted from an indirect bandgap to direct bandgap by an applied electric field and strain. Further, the bandgap size of the heterostructure can be effectively changed and finally make a semiconductor-to-metal transition at electric fields of 0.7 V/Å and strains of −9%. In addition, the optical absorption coefficient of heterojunction relative to the two monolayers has been enhanced, reaching a surprisingly 1.03 × 10⁶ cm⁻¹ at 148.5 nm. This investigation of InSe/HfS₂ heterostructure can provide a theoretical basis for the application in future photoelectric devices.
The effect of biaxial strain on the electronic structures and optical properties of GaS/SSnSe heterojunction: A first-principles calculations
2023, Physics Letters, Section A: General, Atomic and Solid State Physics
Due to their tunable electronic structures and superior optical properties, vertically stacked heterojunctions have received considerable attention. In this paper, the electronic structure, charge transfer, and optical properties of the GaS/SSnSe heterojunction are investigated by first-principles calculations. According to our findings, the GaS/SSnSe heterojunction is a semiconductor with an indirect band gap and a Type-I band alignment. The band alignment of the heterojunction can be linearly tuned by the biaxial strain, which induces a semiconductor-to-metal transition. Moreover, the absorption coefficient of the heterojunction becomes higher and the absorption spectrum appears blue-shifted compared to each monolayer material. The above findings provide a theoretical support for the application of the heterojunction in ultraviolet light detection and tunable devices fields.
First-principles study on the optoelectronic properties of the quasi-one-dimensional flexible semiconductor K<inf>2</inf>PdPS<inf>4</inf>I
2023, Results in Physics
Inorganic semiconductors have superior electrical properties than organic semiconductors, but their application in some devices, such as wearable electronic devices, is subject to the limitations of their brittleness. Low-dimensional flexible inorganic semiconductors have superior electrical properties than organic semiconductors, but their application in some devices, such as wearable electronic devices, is subject to the limitations of their brittleness. Low-dimensional flexible inorganic semiconductors are promising candidates to overcome these disadvantages. Therefore, we pay our attention to a quasi-one-dimensional (Q-1D) chain-like material K₂PdPS₄I and explore its structural stability, electronic structure and optical properties by first-principles calculations. The phonon spectrum of K₂PdPS₄I is dynamically stable without any imaginary frequency. Furthermore, the orthorhombic crystal structure of K₂PdPS₄I meets the mechanical stability criterion according to the calculated elastic tensors. K₂PdPS₄I exhibits anisotropic mechanical properties and belongs to the ductile materials. K₂PdPS₄I is an indirect bandgap semiconductor with obviously anisotropic carrier effective masses and mobility, showing excellent light absorption ability in the visible and ultraviolet regions. The superior mechanical performance and excellent optoelectronic properties enable K₂PdPS₄I as a candidate material for promising applications as low-dimensional flexible optoelectronic semiconductors. The present study not only provides a meaningful supplement for the research of low-dimensional semiconductors, but also will attract extensive interest from a wide audience to explore the Q-1D materials.

View all citing articles on Scopus

View full text

Two-dimensional MgP3 monolayer with remarkably tunable bandgap and enhanced visible-light and UV optical absorptions

Highlights

Abstract

Graphical abstract

Introduction

Section snippets

Computational method

Geometry and stability of the MgP3 monolayer

Conclusion

Author statement

Declaration of competing interest

Acknowledgments

J. Nucel Mater.

Superlattice. Microst.

Appl. Surf. Sci.

Superlattice. Microst.

Physica. E

Renew. Sustain. Energy Rev.

J. Catal.

J. Alloys Compd.

Opt Commun.

Renew. Energy

Int. J. Hydrogen Energy

Superlattice. Microst.

Science

Chem. Rev.

Angew. Chem. Int. Ed.

ACS Nano

J. Phys. Chem. C

Angew. Chem.

Nano Lett.

Appl. Phys. Lett.

Nat. Nanotechnol.

Nat. Commun.

Small

ACS Nano

Nano Lett.

Nano Lett.

Phys. Rev. B

Adv. Energy Mater.

J. Mater. Chem. C

J. Mater. Chem.

Ceram. Int.

J. Mater. Sci.

Two-dimensional MgP₃ monolayer with remarkably tunable bandgap and enhanced visible-light and UV optical absorptions

Geometry and stability of the MgP₃ monolayer