Please use this identifier to cite or link to this item: http://hdl.handle.net/2445/32208
Title: Structural factors impacting carrier transport and electroluminescence from Si nanocluster-sensitized Er ions.
Author: Cueff, Sébastien
Labbé, Christophe
Jambois, Olivier
Berencén Ramírez, Yonder Antonio
Kenyon, Anthony J.
Garrido Fernández, Blas
Rizk, Richard
Keywords: Optoelectrònica
Metalls de terres rares
Nanoestructures
Ions
Optoelectronics
Rare earth metals
Nanostructures
Ions
Issue Date: 17-Sep-2012
Publisher: Optical Society of America
Abstract: We present an analysis of factors influencing carrier transport and electroluminescence (EL) at 1.5 µm from erbium-doped silicon-rich silica (SiOx) layers. The effects of both the active layer thickness and the Si excess content on the electrical excitation of erbium are studied. We demonstrate that when the thickness is decreased from a few hundred to tens of nanometers the conductivity is greatly enhanced. Carrier transport is well described in all cases by a Poole-Frenkel mechanism, while the thickness-dependent current density suggests an evolution of both density and distribution of trapping states induced by Si nanoinclusions. We ascribe this observation to stress-induced effects prevailing in thin films, which inhibit the agglomeration of Si atoms, resulting in a high density of sub-nm Si inclusions that induce traps much shallower than those generated by Si nanoclusters (Si-ncs) formed in thicker films. There is no direct correlation between high conductivity and optimized EL intensity at 1.5 µm. Our results suggest that the main excitation mechanism governing the EL signal is impact excitation, which gradually becomes more efficient as film thickness increases, thanks to the increased segregation of Si-ncs, which in turn allows more efficient injection of hot electrons into the oxide matrix. Optimization of the EL signal is thus found to be a compromise between conductivity and both number and degree of segregation of Si-ncs, all of which are governed by a combination of excess Si content and sample thickness. This material study has strong implications for many electrically driven devices using Si-ncs or Si-excess mediated EL.
It is part of: Optics Express, 2012, vol. 20, num. 20, p. 22490-22502
URI: http://hdl.handle.net/2445/32208
ISSN: 1094-4087
Appears in Collections:Articles publicats en revistes (Electrònica)

Files in This Item:
File Description SizeFormat 
616085.pdf1.74 MBAdobe PDFView/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.