Size-dependent strain relaxation and optical characteristics of InGaN/GaN nanorod LEDs

Yuh Renn Wu*, Chinghua Chiu, Cheng Yu Chang, Pei-Chen Yu, Hao-Chung Kuo

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

75 Scopus citations


In this paper, InGaN/GaN nanorod LEDs with various sizes are fabricated using self-assembled Ni nanomasks and inductively coupled plasma-reactive ion etching. Photoluminescence (PL) characteristics exhibit size-dependent, wavelength blue shifts of the emission spectra from the nanorod LEDs. Numerical analyses using a valence force field model and a self-consistent Poisson, Schrdinger, and drift-diffusion solver quantitatively describe the correlation between the wavelength blue shifts and the strain relaxation of multiple quantum wells embedded in nanorods with different averaged sizes. Time-resolved PL studies confirm that the array with a smaller size exhibits a shorter carrier lifetime at low temperature, giving rise to a stronger PL intensity. However, the PL intensity deteriorates at room temperature, compared to that of a larger size, possibly due to an increased number of surface states, which decreases the nonradiative lifetime, and hence reduces the internal quantum efficiency.

Original languageEnglish
Article number4798202
Pages (from-to)1226-1233
Number of pages8
JournalIEEE Journal on Selected Topics in Quantum Electronics
Issue number4
StatePublished - 10 Mar 2009


  • LEDs
  • Nanotechnology

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