Defect structure and optical phonon confinement in ultrananocrystalline BixSn1-xO2 (x = 0, 0.03, 0.05, and 0.08) synthesized by a sonochemical method

L. Aswaghosh, Divinah Manoharan, N. Victor Jaya

研究成果: Article同行評審

34 引文 斯高帕斯(Scopus)

摘要

We report the structure of defect and the oxygen vacancy-induced optical phonon confinement in phase pure tetragonal rutile crystal structured ultrananocrystalline BixSn1-xO2 (x = 0, 0.03, 0.05, 0.08) with high surface area synthesized by sonochemical method. As the Bi ion incorporates into the SnO2 host lattice, it replaces the Sn ions marked by the lattice expansion, which leads to the formation of oxygen vacancies so as to maintain charge neutrality. The grain size reduces from 6 nm to 3 nm with increase in Bi content from 0% to 8%. The size effect and the increased oxygen vacancy concentration were found to induce phonon confinement within the grain. This has led to interesting changes in the vibrational spectra of the ultrananocrystalline BixSn1-xO2 as the size reduces below 9 nm. Absence of periodicity beyond this critical particle size relaxes the zone-centre optical phonon selection rule, causing the Raman spectrum to have contributions also from phonons away from the Brillouin-zone centre. The structure of defects, such as the in-plane, bridging and sub-bridging oxygen vacancies present, was confirmed using Raman spectroscopic analysis. The reason for enhancement in photoluminescence behaviour with increased Bi content is discussed. The energy band gap was found to be wider (∼4 eV) compared to the bulk and reveals an increasing trend as a function of Bi%. The increase in band gap with decrease in particle size marks the quantum confinement effect. The variation of band gap upon doping is due to the BM shift effect, which arises as a result of the increase in carrier concentration.

原文English
頁(從 - 到)5995-6004
頁數10
期刊Physical Chemistry Chemical Physics
18
發行號8
DOIs
出版狀態Published - 2016 1月 1

All Science Journal Classification (ASJC) codes

  • 物理與天文學 (全部)
  • 物理與理論化學

指紋

深入研究「Defect structure and optical phonon confinement in ultrananocrystalline BixSn1-xO2 (x = 0, 0.03, 0.05, and 0.08) synthesized by a sonochemical method」主題。共同形成了獨特的指紋。

引用此