Benchmark Investigation of Band-Gap Tunability of Monolayer Semiconductors under Hydrostatic Pressure with Focus-On Antimony

In this paper, the band-gap tunability of three monolayer semiconductors under hydrostatic pressure was intensively investigated based on first-principle simulations with a focus on monolayer antimony (Sb) as a semiconductor nanomaterial. As the benchmark study, monolayer black phosphorus (BP) and monolayer molybdenum disulfide (MoS2) were also investigated for comparison. Our calculations showed that the band-gap tunability of the monolayer Sb was much more sensitive to hydrostatic pressure than that of the monolayer BP and MoS2. Furthermore, the monolayer Sb was predicted to change from an indirect band-gap semiconductor to a conductor and to transform into a double-layer nanostructure above a critical pressure value ranging from 3 to 5 GPa. This finding opens an opportunity for nanoelectronic, flexible electronics and optoelectronic devices as well as sensors with the capabilities of deep band-gap tunability and semiconductor-to-metal transition by applying mechanical pressure.

Download Full-text

Electric Field Controlled Indirect-Direct-Indirect Band Gap Transition in Monolayer InSe

Nanoscale Research Letters ◽

10.1186/s11671-019-3162-0 ◽

2019 ◽

Vol 14 (1) ◽

Author(s):

Xian-Bo Xiao ◽

Qian Ye ◽

Zheng-Fang Liu ◽

Qing-Ping Wu ◽

Yuan Li ◽

...

Keyword(s):

Field Strength ◽

Electric Field ◽

Electric Field Strength ◽

Band Gap ◽

Energy Band ◽

Electronic Structures ◽

Optoelectronic Devices ◽

Group Iii ◽

Underlying Mechanisms ◽

Indirect Band Gap

Abstract Electronic structures of monolayer InSe with a perpendicular electric field are investigated. Indirect-direct-indirect band gap transition is found in monolayer InSe as the electric field strength is increased continuously. Meanwhile, the global band gap is suppressed gradually to zero, indicating that semiconductor-metal transformation happens. The underlying mechanisms are revealed by analyzing both the orbital contributions to energy band and evolution of band edges. These findings may not only facilitate our further understanding of electronic characteristics of layered group III-VI semiconductors, but also provide useful guidance for designing optoelectronic devices.

Download Full-text

First principle insight on the structural, mechanical, electronic and optical properties of indirect band gap photovoltaic material Cs2NaBiX6 (X= Cl, Br, I)

Computational Condensed Matter ◽

10.1016/j.cocom.2021.e00581 ◽

2021 ◽

pp. e00581

Author(s):

Radhakrishnan Anbarasan ◽

Jeyaperumal Kalyana Sundar ◽

Manikkam Srinivasan ◽

Perumalsamy Ramasamy

Keyword(s):

Optical Properties ◽

Band Gap ◽

First Principle ◽

Electronic And Optical Properties ◽

Indirect Band Gap ◽

Photovoltaic Material

Download Full-text

First-Principles Study on the Effect of Strain on Single-Layer Molybdenum Disulfide

Nanomaterials ◽

10.3390/nano11113127 ◽

2021 ◽

Vol 11 (11) ◽

pp. 3127

Author(s):

Chen Chong ◽

Hongxia Liu ◽

Shulong Wang ◽

Kun Yang

Keyword(s):

Band Gap ◽

Molybdenum Disulfide ◽

Density Of States ◽

First Principles ◽

Density Functional ◽

Single Layer ◽

Small Strain ◽

Structure Changes ◽

Calculation Results ◽

Indirect Band Gap

By adopting the first-principles plane wave pseudopotential method based on density functional theory, the electronic structure properties of single-layer MoS2 (molybdenum disulfide) crystals under biaxial strain are studied. The calculation results in this paper show that when a small strain is applied to a single-layer MoS2, its band structure changes from a direct band gap to an indirect band gap. As the strain increases, the energy band still maintains the characteristics of the indirect band gap, and the band gap shows a linear downward trend. Through further analysis of the density of states, sub-orbital density of states, thermodynamic parameters and Raman spectroscopy, it revealed the variation of single-layer MoS2 with strain. This provides a theoretical basis for realizing the strain regulation of MoS2.

Download Full-text

Computational Envision of Structural, Electronic, Mechanical and Thermoelectric Properties of PdXSn (X=Zr, Hf) half Heusler compounds

10.22541/au.164139751.17968957/v1 ◽

2022 ◽

Author(s):

Bindu Rani ◽

Aadil Wani ◽

Utkir Sharopov ◽

Kulwinder Kaur ◽

Shobhna Dhiman

Keyword(s):

Band Gap ◽

Thermoelectric Properties ◽

Lattice Thermal Conductivity ◽

First Principle ◽

Heusler Compounds ◽

Boltzmann Transport ◽

Principle Calculation ◽

First Principle Calculation ◽

Good Thermal Stability ◽

Indirect Band Gap

Half heusler compounds have gained attention due to their excellent properties and good thermal stability. In this paper, using first principle calculation and Boltzmann transport equation, we have investigated structural, electronic, mechanical and thermoelectric properties of PdXSn (X=Zr,Hf) half Heusler materials. These materials are indirect band gap semiconductors with band gap of 0.52 (0.44) for PdZrSn (PdHfSn). Calculations of elastic and phonon characteristics show that both materials are mechanically and dynamically stable. At 300K the magnitude of lattice thermal conductivity observed for PdZrSn is 15.16 W/mK and 9.53 W/mK for PdHfSn. The highest ZT value for PdZrSn and PdHfSn is 0.32 and 0.4 respectively.

Download Full-text

A First-Principle Calculation of the Temperature Dependence of the Indirect Band Gap of Silicon

EPL (Europhysics Letters) ◽

10.1209/0295-5075/10/6/011 ◽

1989 ◽

Vol 10 (6) ◽

pp. 569-574 ◽

Cited By ~ 40

Author(s):

R. D King-Smith ◽

R. J Needs ◽

V Heine ◽

M. J Hodgson

Keyword(s):

Temperature Dependence ◽

Band Gap ◽

First Principle ◽

Principle Calculation ◽

First Principle Calculation ◽

Indirect Band Gap

Download Full-text

First-Principle Calculation of High Absorption-TlGaTe2 for Photovoltaic Application

Materials ◽

10.3390/ma12172667 ◽

2019 ◽

Vol 12 (17) ◽

pp. 2667

Author(s):

Murugesan Rasukkannu ◽

Dhayalan Velauthapillai ◽

Ponniah Vajeeston

Keyword(s):

Band Gap ◽

Functional Model ◽

Visible Region ◽

Potential Candidate ◽

First Principle ◽

Hybrid Functional ◽

First Principle Calculation ◽

Photovoltaic Application ◽

Direct Band ◽

Indirect Band Gap

We use first-principle calculations based on hybrid functional and the Bethe-Salpeter equation method to investigate the electronic and optical properties of dichalcogenide TlGaTe2. Based on theoretical studies, TlGaTe2 has until recently been considered as an indirect band gap material, however; by employing more accurate hybrid functional model, we showed that although TlGaTe2 has an indirect band gap of 1.109 eV, it also exhibits a fundamental direct band gap of 1.129 eV. Our finding was further confirmed by the optical studies on TlGaTe2, which show that the absorption peak is registered at a photon energy of 1.129 eV. It was also shown that TlGaTe2 has high optical absorption peaks in the visible region. Based on phonon and elastic constant calculations, it was shown that TlGaTe2 is dynamically and mechanically stable. Our findings show that TlGaTe2 is a potential candidate for photovoltaic application.

Download Full-text

First-Principle Study of the Structural, Electronic, and Optical Properties of Cubic InNxP1–x Ternary Alloys under Hydrostatic Pressure

Zeitschrift für Naturforschung A ◽

10.1515/zna-2016-0100 ◽

2016 ◽

Vol 71 (9) ◽

pp. 783-796 ◽

Cited By ~ 3

Author(s):

I. Hattabi ◽

A. Abdiche ◽

R. Moussa ◽

R. Riane ◽

K. Hadji ◽

...

Keyword(s):

Experimental Data ◽

Optical Properties ◽

Hydrostatic Pressure ◽

Bulk Modulus ◽

Band Gap ◽

Lattice Constant ◽

First Principle ◽

Electronic Band ◽

Electronic And Optical Properties ◽

Good Agreement

AbstractIn this article, we present results of the first-principle study of the structural, electronic, and optical properties of the InN, InP binary compounds and their related ternary alloy InNxP1–x in the zinc-blend (ZB) phase within a nonrelativistic full potential linearised augmented plan wave (FP-LAPW) method using Wien2k code based on the density functional theory (DFT). Different approximations of exchange–correlation energy were used for the calculation of the lattice constant, bulk modulus, and first-order pressure derivative of the bulk modulus. Whereas the lattice constant decreases with increasing nitride composition x. Our results present a good agreement with theoretical and experimental data. The electronic band structures calculated using Tran-Blaha-modified Becke–Johnson (TB-mBJ) approach present a direct band gap semiconductor character for InNxP1–x compounds at different x values. The electronic properties were also calculated under hydrostatic pressure for (P=0.00, 5.00, 10.0, 15.0, 20.0, 25.0 GPa) where it is found that the InP compound change from direct to indirect band gap at the pressure P≥7.80 GPa. Furthermore, the pressure effect on the dielectric function and the refractive index was carried out. Results obtained in our calculations present a good agreement with available theoretical reports and experimental data.

Download Full-text

Tunability of Structure, Polarization, and Band Gap of High TC Organic–Inorganic Ferroelectrics by Hydrostatic Pressure: First-Principles Study

The Journal of Physical Chemistry C ◽

10.1021/acs.jpcc.1c03980 ◽

2021 ◽

Author(s):

P. S. Ghosh ◽

J. Doherty ◽

S. Lisenkov ◽

I. Ponomareva

Keyword(s):

Hydrostatic Pressure ◽

Band Gap ◽

First Principles ◽

High Tc ◽

First Principles Study

Download Full-text

Encapsulated Passivation of Perovskite Quantum Dot (CsPbBr3) Using a Hot-Melt Adhesive (EVA-TPR) for Enhanced Optical Stability and Efficiency

Crystals ◽

10.3390/cryst11040419 ◽

2021 ◽

Vol 11 (4) ◽

pp. 419

Author(s):

Saradh Prasad ◽

Mamduh J. Aljaafreh ◽

Mohamad S. AlSalhi ◽

Abeer Alshammari

Keyword(s):

Quantum Dots ◽

Band Gap ◽

Surface Defects ◽

Optoelectronic Devices ◽

Ethylene Vinyl Acetate ◽

Light Emitting ◽

Optical Stability ◽

Perovskite Quantum Dots ◽

Polymer Light Emitting Diodes ◽

Hot Melt

The notable photophysical characteristics of perovskite quantum dots (PQDs) (CsPbBr3) are suitable for optoelectronic devices. However, the performance of PQDs is unstable because of their surface defects. One way to address the instability is to passivate PQDs using different organic (polymers, oligomers, and dendrimers) or inorganic (ZnS, PbS) materials. In this study, we performed steady-state spectroscopic investigations to measure the photoluminescence (PL), absorption (A), transmission (T), and reflectance (R) of perovskite quantum dots (CsPbBr3) and ethylene vinyl acetate/terpene phenol (1%) (EVA-TPR (1%), or EVA) copolymer/perovskite composites in thin films with a thickness of 352 ± 5 nm. EVA is highly transparent because of its large band gap; furthermore, it is inexpensive and easy to process. However, the compatibility between PQDs and EVA should be established; therefore, a series of analyses was performed to compute parameters, such as the band gap, the coefficients of absorbance and extinction, the index of refractivity, and the dielectric constant (real and imaginary parts), from the data obtained from the above investigation. Finally, the optical conductivities of the films were studied. All these analyses showed that the EVA/PQDs were more efficient and stable both physically and optically. Hence, EVA/PQDs could become copolymer/perovskite active materials suitable for optoelectronic devices, such as solar cells and perovskite/polymer light-emitting diodes (PPLEDs).

Download Full-text

Transparent All-Oxide Hybrid NiO:N/TiO2 Heterostructure for Optoelectronic Applications

Electronics ◽

10.3390/electronics10090988 ◽

2021 ◽

Vol 10 (9) ◽

pp. 988

Author(s):

Chrysa Aivalioti ◽

Alexandros Papadakis ◽

Emmanouil Manidakis ◽

Maria Kayambaki ◽

Maria Androulidaki ◽

...

Keyword(s):

Band Gap ◽

Single Phase ◽

Structural Disorder ◽

Energy Band Gap ◽

Nitrogen Doped ◽

Nio Thin Film ◽

Direct Band ◽

Output Characteristics ◽

Indirect Band Gap ◽

P Type

Nickel oxide (NiO) is a p-type oxide and nitrogen is one of the dopants used for modifying its properties. Until now, nitrogen-doped NiO has shown inferior optical and electrical properties than those of pure NiO. In this work, we present nitrogen-doped NiO (NiO:N) thin films with enhanced properties compared to those of the undoped NiO thin film. The NiO:N films were grown at room temperature by sputtering using a plasma containing 50% Ar and 50% (O2 + N2) gases. The undoped NiO film was oxygen-rich, single-phase cubic NiO, having a transmittance of less than 20%. Upon doping with nitrogen, the films became more transparent (around 65%), had a wide direct band gap (up to 3.67 eV) and showed clear evidence of indirect band gap, 2.50–2.72 eV, depending on %(O2-N2) in plasma. The changes in the properties of the films such as structural disorder, energy band gap, Urbach states and resistivity were correlated with the incorporation of nitrogen in their structure. The optimum NiO:N film was used to form a diode with spin-coated, mesoporous on top of a compact, TiO2 film. The hybrid NiO:N/TiO2 heterojunction was transparent showing good output characteristics, as deduced using both I-V and Cheung’s methods, which were further improved upon thermal treatment. Transparent NiO:N films can be realized for all-oxide flexible optoelectronic devices.

Download Full-text