Role of defect saturation in improving optical response from InGaN nanowires in higher wavelength regime

Dhiman Nag, Ritam Sarkar, Swagata Bhunia, Tarni Aggarwal, Kankat Ghosh, Shreekant Sinha, Swaroop Ganguly, Dipankar Saha, Ray Hua Horng, Apurba Laha*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Growth of InGaN, having high Indium composition without compromising crystal quality has always been a great challenge to obtain efficient optical devices. In this work, we extensively study the impact of non-radiative defects on optical response of the plasma assisted molecular beam epitaxy (PA-MBE) grown InGaN nanowires, emitting in the higher wavelength regime (lambda > 520 nm). Our analysis focuses into the effect of defect saturation on the optical output, manifested by photoluminescence (PL) spectroscopy. Defect saturation has not so far been thoroughly investigated in InGaN based systems at such a high wavelength, where defects play a key role in restraining efficient optical performance. We argue that with saturation of defect states by photo-generated carriers, the advantages of carrier localization can be employed to enhance the optical output. Carrier localization arises because of Indium phase segregation, which is confirmed from wide PL spectrum and analysis from transmission electron microscopy (TEM). A theoretical model has been proposed and solved using coupled differential rate equations in steady state to undertake different phenomena, occurred during PL measurements. Analysis of the model helps us understand the impact of non-radiative defects on PL response and identifying the origin of enhanced radiative recombination.

Original languageEnglish
Article number495705
Number of pages9
JournalNanotechnology
Volume31
Issue number49
DOIs
StatePublished - 4 Dec 2020

Keywords

  • Enhanced radiative recombination
  • Green gap
  • InGaN nanowires
  • Plasma assisted molecular beam epitaxy

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