Strain relaxation in GaNxP1-x alloy: Effect on optical properties

I. A. Buyanova*, W. M. Chen, E. M. Goldys, M. R. Phillips, H. P. Xin, C. W. Tu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

By using scanning electron microscopy and cathodoluminescence (CL), a decrease in radiative efficiency of GaNP alloy with increasing N content is seen due to the formation of structural defects. The defect formation is attributed to relaxation of tensile strain in the GaNP layer, which is lattice mismatched to GaP substrate. Several types of extended defects including dislocations, microcracks and pits are revealed in partly relaxed GaNxP1-x epilayers with x≥1.9%, whereas coherently strained layers exhibit high crystalline quality for x up to 4%. According to the CL measurements, all extended defects act as competing, non-radiative channels leading to the observed strong decrease in the radiative efficiency. From CL mapping experiments, non-uniformity of strain distribution around the extended defects is partly responsible for the broadening of the photoluminescence (PL) spectra recorded in the macro-PL experiments.

Original languageEnglish
Pages (from-to)106-109
Number of pages4
JournalPhysica B: Condensed Matter
Volume308-310
DOIs
Publication statusPublished - Dec 2001

Keywords

  • Extended defects
  • GANP
  • Luminescence
  • Strain

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