Well-width dependence of the emission linewidth in ZnO/MgZnO quantum wells

Xue Qin Lv, Jiang Yong Zhang, Lei Ying Ying, Wen Jie Liu, Xiao Long Hu, Bao Ping Zhang, Zhi Ren Qiu, Shigeyuki Kuboya, Kentaro Onabe

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Photoluminescence (PL) spectra were measured as a function of well width (LW) and temperature in ZnO/ Mg0.1Zn0.9O single quantum wells (QWs) with graded thickness. The emission linewidth (full width at half maximum) was extracted from the emission spectra, and its variation as a function of LW was studied. The inhomogeneous linewidth obtained at 5 K was found to decrease with increasing LW from 1.8 to 3.3 nm due to the reduced potential variation caused by the LW fluctuation. Above 3.3 nm, however, the linewidth became larger with increasing LW, which was explained by the effect related with defect generation due to strain relaxation and exciton expansion in the QW. For the homogenous linewidth broadening, longitudinal optical (LO) phonon scattering and impurity scattering were taken into account. The LO phonon scattering coefficient ΓLO and impurity scattering coefficient Γimp were deduced from the temperature dependence of the linewidth of the PL spectra. Evident reduction of ΓLO with decreasing LW was observed, which was ascribed to the confinement-induced enhancement of the exciton binding energy. Different from ΓLO, a monotonic increase in Γimp was observed with decreasing LW, which was attributed to the enhanced penetration of the exciton wave function into the barrier layers.

Original languageEnglish
Article number605
Pages (from-to)1-5
Number of pages5
JournalNanoscale Research Letters
Volume7
DOIs
Publication statusPublished - 2012

Keywords

  • Linewidth
  • Photoluminescence
  • ZnO/MgZnO quantum well

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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