Abstract
High quantum efficiencies and low current thresholds are important properties for all classes of semiconductor light emitting devices (LEDs), including nanoscale emitters based on single wall carbon nanotubes (SWNTs). Among the various configurations that can be considered in SWNT LEDs, two terminal geometries with asymmetric metal contacts offer the simplest solution. In this paper, we study, experimentally and theoretically, the mechanisms of electroluminescence in devices that adopt this design and incorporate perfectly aligned, horizontal arrays of individual SWNTs. The results suggest that exciton mediated electron-hole recombination near the lower work-function contact is the dominant source of photon emission. High current thresholds for electroluminescence in these devices result from diffusion and quenching of excitons near the metal contact.
Original language | English (US) |
---|---|
Pages (from-to) | 7981-7988 |
Number of pages | 8 |
Journal | ACS nano |
Volume | 6 |
Issue number | 9 |
DOIs | |
State | Published - Sep 25 2012 |
Keywords
- Single-wall carbon nanotube
- asymmetric contact
- electroluminescence
- electron-hole recombination
- exciton
- luminescence quenching
ASJC Scopus subject areas
- Engineering(all)
- Physics and Astronomy(all)
- Materials Science(all)