Emission enhancement, light extraction and carrier dynamics in ingaas/gaas nanowire arrays

Pyry Kivisaari*, Yang Chen, Nicklas Anttu

*Corresponding author for this work

Research output: Contribution to journalComment/debateScientificpeer-review

11 Citations (Scopus)

Abstract

Nanowires (NWs) have the potential for a wide range of new optoelectronic applications. For example, light-emitting diodes that span over the whole visible spectrum are currently being developed from NWs to overcome the well known green gap problem. However, due to their small size, NW devices exhibit special properties that complicate their analysis, characterization, and further development. In this paper, we develop a full optoelectronic simulation tool for NW array light emitters accounting for carrier transport and wave-optical emission enhancement (EE), and we use the model to simulate InGaAs/GaAs NW array light emitters with different geometries and temperatures. Our results show that NW arrays emit light preferentially to certain angles depending on the NW diameter and temperature, encouraging temperature-and angle-resolved measurements of NW array light emission. On the other hand, based on our results both the EE and light extraction efficiency can easily change by at least a factor of two between room temperature and 77 K, complicating the characterization of NW light emitters if conventional methods are used. Finally, simulations accounting for surface recombination emphasize its major effect on the device performance. For example, a surface recombination velocity of 104 cm s−1 reported earlier for bare InGaAs surfaces results in internal quantum efficiencies less than 30% for small-diameter NWs even at the temperature of 30 K. This highlights that core–shell structures or high-quality passivation techniques are eventually needed to achieve efficient NW-based light emitters.

Original languageEnglish
Article number015001
JournalNano Futures
Volume2
Issue number1
DOIs
Publication statusPublished - Mar 2018
MoE publication typeA1 Journal article-refereed

Keywords

  • Emission enhancement
  • Light extraction
  • Light-emitting diodes
  • Nanowire array
  • Semiconductor
  • Surface recombination Supplementary material for this article is available online

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