Tunable Bandgap in BiFeO3 Nanoparticles: The Role of Microstrain and Oxygen Defects: The role of microstrain and oxygen defects

Pavana S.V. Mocherla; C. Karthik; R. Ubic; M. S. Ramachandra Rao; C. Sudakar

doi:10.1063/1.4813539

Tunable Bandgap in BiFeO₃ Nanoparticles: The Role of Microstrain and Oxygen Defects: The role of microstrain and oxygen defects

Pavana S.V. Mocherla, C. Karthik, R. Ubic, M. S. Ramachandra Rao, C. Sudakar

Micron School of Materials Science and Engineering

Research output: Contribution to journal › Article › peer-review

277 Scopus citations

Abstract

We demonstrate a tunable bandgap from 2.32 eV to 2.09 eV in phase-pure BiFeO₃ by controlling the particle size from 65 nm to 5 nm. Defect states due to oxygen and microstrain show a strong dependence on BiFeO ₃ particle size and have a significant effect on the shape of absorbance curves. Oxygen-defect induced microstrain and undercoordinated oxygen on the surface of BiFeO₃ nanoparticles are demonstrated via HRTEM and XPS studies. Microstrain in the lattice leads to the reduction in rhombohedral distortion of BiFeO₃ for particle sizes below 30 nm. The decrease in band gap with decreasing particle size is attributed to the competing effects of microstrain, oxygen defects, and Coulombic interactions.

Original language	American English
Article number	022910
Journal	Applied Physics Letters
Volume	103
Issue number	2
DOIs	https://doi.org/10.1063/1.4813539
State	Published - 8 Jul 2013

Keywords

bismuth compounds
defect states
energy gap
infrared spectra
multiferroics
nanoparticles
particle size
transmission electron microscopy
ultraviolet spectra
visible spectra
X-ray photoelectron spectra

EGS Disciplines

Materials Science and Engineering

Access to Document

10.1063/1.4813539

https://doi.org/10.1063/1.4813539

Cite this

@article{bc3854f643ed4d8a9004f56799ea303d,

title = "Tunable Bandgap in BiFeO3 Nanoparticles: The Role of Microstrain and Oxygen Defects: The role of microstrain and oxygen defects",

abstract = "We demonstrate a tunable bandgap from 2.32 eV to 2.09 eV in phase-pure BiFeO3 by controlling the particle size from 65 nm to 5 nm. Defect states due to oxygen and microstrain show a strong dependence on BiFeO 3 particle size and have a significant effect on the shape of absorbance curves. Oxygen-defect induced microstrain and undercoordinated oxygen on the surface of BiFeO3 nanoparticles are demonstrated via HRTEM and XPS studies. Microstrain in the lattice leads to the reduction in rhombohedral distortion of BiFeO3 for particle sizes below 30 nm. The decrease in band gap with decreasing particle size is attributed to the competing effects of microstrain, oxygen defects, and Coulombic interactions.",

keywords = "bismuth compounds, defect states, energy gap, infrared spectra, multiferroics, nanoparticles, particle size, transmission electron microscopy, ultraviolet spectra, visible spectra, X-ray photoelectron spectra",

author = "Mocherla, {Pavana S.V.} and C. Karthik and R. Ubic and {Ramachandra Rao}, {M. S.} and C. Sudakar",

year = "2013",

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doi = "10.1063/1.4813539",

language = "American English",

volume = "103",

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TY - JOUR

T1 - Tunable Bandgap in BiFeO3 Nanoparticles: The Role of Microstrain and Oxygen Defects

T2 - The role of microstrain and oxygen defects

AU - Mocherla, Pavana S.V.

AU - Karthik, C.

AU - Ubic, R.

AU - Ramachandra Rao, M. S.

AU - Sudakar, C.

PY - 2013/7/8

Y1 - 2013/7/8

N2 - We demonstrate a tunable bandgap from 2.32 eV to 2.09 eV in phase-pure BiFeO3 by controlling the particle size from 65 nm to 5 nm. Defect states due to oxygen and microstrain show a strong dependence on BiFeO 3 particle size and have a significant effect on the shape of absorbance curves. Oxygen-defect induced microstrain and undercoordinated oxygen on the surface of BiFeO3 nanoparticles are demonstrated via HRTEM and XPS studies. Microstrain in the lattice leads to the reduction in rhombohedral distortion of BiFeO3 for particle sizes below 30 nm. The decrease in band gap with decreasing particle size is attributed to the competing effects of microstrain, oxygen defects, and Coulombic interactions.

AB - We demonstrate a tunable bandgap from 2.32 eV to 2.09 eV in phase-pure BiFeO3 by controlling the particle size from 65 nm to 5 nm. Defect states due to oxygen and microstrain show a strong dependence on BiFeO 3 particle size and have a significant effect on the shape of absorbance curves. Oxygen-defect induced microstrain and undercoordinated oxygen on the surface of BiFeO3 nanoparticles are demonstrated via HRTEM and XPS studies. Microstrain in the lattice leads to the reduction in rhombohedral distortion of BiFeO3 for particle sizes below 30 nm. The decrease in band gap with decreasing particle size is attributed to the competing effects of microstrain, oxygen defects, and Coulombic interactions.

KW - bismuth compounds

KW - defect states

KW - energy gap

KW - infrared spectra

KW - multiferroics

KW - nanoparticles

KW - particle size

KW - transmission electron microscopy

KW - ultraviolet spectra

KW - visible spectra

KW - X-ray photoelectron spectra

UR - https://scholarworks.boisestate.edu/mse_facpubs/159

UR - https://doi.org/10.1063/1.4813539

U2 - 10.1063/1.4813539

DO - 10.1063/1.4813539

M3 - Article

SN - 0003-6951

VL - 103

JO - Applied Physics Letters

JF - Applied Physics Letters

IS - 2

M1 - 022910

ER -