Structural factors impacting carrier transport and electroluminescence from Si nanocluster-sensitized Er ions

Abstract

Abstract:We present an analysis of factors influencing carrier transport and electroluminescence (EL) at 1.5 µm from erbium-doped silicon-rich silica (SiO x ) layers. The effects of both the active layer thickness and the Siexcess 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 electricallydriven devices using Si-ncs or Si-excess mediated EL. USSR 5, 685-687 (1938). ©2012 Optical Society of America

Dynamic control of light emission faster than the lifetime limit using VO2 phase-change

“…While this initial demonstration focused on all-optical modulation, switching of VO 2 could also be produced by electrically triggering the IMT 24 25 (see Supplementary Note 2 for discussion of switching energy). Combined with electroluminescent devices 26 27 , all-electrical direct modulation of emission could be obtained. The presented concept is not limited to Er 3+ ions and VO 2 .…”

Silicon-Rich Oxide Obtained by Low-Pressure Chemical Vapor Deposition to Develop Silicon Light Sources

“…Basically, there are four main mechanisms known to contribute in the carrier transport through a Si-rich oxide layer, including the direct tunneling, Fowler Nordheim tunneling (F-N), Poole-Frenkel (P-F) and the trap-assisted tunneling (TAT) [33][34][35][36][37]. It has been found that the TAT conduction mechanism predominates in our SRO 30 -based LECs, where the trap energy (ϕ t ) was estimated at about 1.99 eV [28].…”

Quantifying and controlling the magnetic dipole contribution to1.5−μmlight emission in erbium-doped yttrium oxide

“…1 For decades, spontaneous emission from Er 3+ ions has been investigated for applications in integrated optics, [2][3][4][5][6] including recent work exploring enhanced Er 3+ emission within optical nanostructures as the basis for chip-scale devices. [7][8][9][10][11][12][13] Spontaneous emission from Er 3+ also serves as the basis for the upconverting phosphors used in silicon-based near-infrared cameras, 14 and recent work has shown how upconverting erbium-doped nanoparticles can serve as low-background, photo-stable light sources for microscopy and bio-imaging. [15][16][17] In addition to its technological importance, Er 3+ light emission has been the subject of numerous scientific studies, including canonical experiments on the study of lightmatter interactions.…”