Effective band gap inhomogeneity and piezoelectric field in InGaN/GaN multiquantum well structures

S. F. Chichibu*, A. C. Abare, M. S. Minsky, S. Keller, S. B. Fleischer, J. E. Bowers, E. Hu, U. K. Mishra, L. A. Coldren, S. P. Denbaars, T. Sota

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

434 Citations (Scopus)

Abstract

The emission mechanisms of strained InxGa1-xN quantum wells (QWs) were shown to vary depending on the well thickness, L, and x. The absorption edge was modulated by the quantum confined Stark effect and quantum confined Franz-Keldysh effect (QCFK) for the wells, in which, for the first approximation, the product of the piezoelectric field, FPZ, and L exceed the valence band discontinuity, ΔEV. In this case, holes are confined in the triangular potential well formed at one side of the well producing the apparent Stokes-like shift. Under the condition that FPZ×L exceeds the conduction band discontinuity ΔEC, the electron-hole pair is confined at opposite sides of the well. The QCFK further modulated the emission energy for the wells with L greater than the three dimensional free exciton Bohr radius aB. On the other hand, effective in-plane localization of carriers in quantum disk size potential minima, which are produced by nonrandom alloy compositional fluctuation enhanced by the large bowing parameter and FPZ, produces a confined electron-hole pair whose wave functions are still overlapped (quantized excitons) provided that L<aB.

Original languageEnglish
Pages (from-to)2006-2008
Number of pages3
JournalApplied Physics Letters
Volume73
Issue number14
DOIs
Publication statusPublished - 1998

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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