Surface Plasmon Polariton Cross-Coupling Enhanced Forward Emission from Insulator-Metal-Capped ZnO Films

Dangyuan Lei, Lei Zhang, Hock Chun Ong

Research output: Journal article publicationJournal articleAcademic researchpeer-review

4 Citations (Scopus)

Abstract

Increasing light extraction efficiency in the forward direction is being extensively pursued due to its crucial role in realizing top-emitting organic and inorganic light emitting devices. Various surface plasmon polariton (SPP)-based strategies for emission enhancement and light extraction have been developed to improve the top-emitting efficiency of these devices. However, the role of surface roughness of both semiconductor film and metal electrode in improving the emission efficiency of a practical device has not been thoroughly studied yet. In this work, the influence of surface roughness of a top metal electrode on the photoluminescence enhancement of a ZnO thin film is investigated experimentally and numerically based on an insulator-metal-semiconductor system. It is found that the generic surface roughness of the metal electrode plays an encouraging role in increasing the forward-emission intensity by facilitating cross-coupling of SPPs on the two opposite sides of the metal layer. More importantly, the forward emission can be further enhanced by capping a high-index polymer layer on the metal electrode to bridge the momentum mismatch between the two SPPs modes. The experimental observations are well explained by the SPPs cross-coupling mechanism that models the radiation power of a dipolar emitter underneath the metal electrode as a function of the metal surface roughness. Our work opens up the possibility of using cross-coupling of SPPs as an effective means to fabricate high-brightness top-emitting devices without the need of complicated nanoscale patterning.
Original languageEnglish
Pages (from-to)23496-23500
Number of pages5
JournalACS Applied Materials and Interfaces
Volume7
Issue number42
DOIs
Publication statusPublished - 28 Oct 2015

Keywords

  • cross-coupling
  • momentum matching
  • photoluminescence
  • roughness
  • surface plasmon polariton
  • ZnO film

ASJC Scopus subject areas

  • Materials Science(all)

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