Tunable bandgap in BiFeO3 nanoparticles: The role of microstrain and oxygen defects

被引：255
作者：
Mocherla, Pavana S. V. [1 ]
Karthik, C. [2 ]
Ubic, R. [2 ]
Rao, M. S. Ramachandra [3 ,4 ]
Sudakar, C. [1 ]
机构：
[1] Indian Inst Technol, Dept Phys, Multifunct Mat Lab, Madras 600036, Tamil Nadu, India
[2] Boise State Univ, Dept Mat Sci & Engn, Boise, ID 83725 USA
[3] Indian Inst Technol, Dept Phys, Madras 600036, Tamil Nadu, India
[4] Indian Inst Technol, Nano Funct Mat Technol Ctr, Madras 600036, Tamil Nadu, India
来源：
APPLIED PHYSICS LETTERS | 2013年 / 103卷 / 02期
关键词：
MICROCRYSTALS; TEMPERATURE; STATES; FILMS;
D O I：
10.1063/1.4813539
中图分类号：
O59 [应用物理学];
学科分类号：
摘要：
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 BiFeO3 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. (C) 2013 AIP Publishing LLC.
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页数：5
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