Bound-exciton-induced current bistability in a silicon light-emitting diode

Sun, Jiaming; Dekorsy, Thomas; Skorupa, W.; Schmidt, Bernd; Helm, M.

doi:10.1063/1.1570920

Cited by 7 publications

(7 citation statements)

References 17 publications

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“…We compare the experimental results to calculations based on a rate-equation model for excitons and free carriers. It is shown that the model quantitatively accounts for an experimentally observed bistability in the I-V characteristics of the diodes [24] as well as the temperature dependence of the luminescence intensity from the diodes. The excellent agreement between theory and experiment points out the role of excitons in the optical and electrical characteristics of the diodes.…”

Section: Introductionmentioning

confidence: 99%

Light-emitting silicon pn diodes

Dekorsy

Sun

Skorupa

et al. 2004

Applied Physics A: Materials Science & Processing

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We report on the electrical and optical characteristics of silicon light-emitting pn diodes. The diodes are prepared by ion implantation of boron at high doses and subsequent hightemperature annealing. Under forward bias, the diodes emit infrared electroluminescence closely below the band gap of bulk Si. We present a rate-equation model for bound excitons, free excitons and free carriers which successfully describes the electrical and optical behaviour of the diodes at low temperatures. Especially, an electrical bistability observed below 50 K is shown to be based on the interplay of bound excitons, free excitons and free carriers in the active area of the diodes. The ionisation of bound excitons is the origin of an improved electroluminescence from the diodes at higher lattice temperatures.PACS 78.60.Fi; 78.55.Ap; 71.55.Cn

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Section: Introductionmentioning

confidence: 99%

Light-emitting silicon pn diodes

Dekorsy

Sun

Skorupa

et al. 2004

Applied Physics A: Materials Science & Processing

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“…In a previous study of low temperature EL spectra of silicon pn diodes we found two luminescence peaks with maxima around 1.05 and 0.95 eV from excitons bound to traps which are introduced by the high-dose boron implantation and the subsequent annealing. 6 A more detailed study indicates that these peaks can be explained by recombination of spatially indirect excitons ͑with electrons and holes localized in spatially separated potential minima͒ which are formed by a locally increased boron concentration in combination with strain-free or highly strained environments surrounding dislocations. 7,8 The strong trapping and detrapping of excitons bound to these traps can strongly influence the conductivity via the free carrier concentration and contribute to an S-type current bistability at low temperature.…”

mentioning

confidence: 99%

“…7,8 The strong trapping and detrapping of excitons bound to these traps can strongly influence the conductivity via the free carrier concentration and contribute to an S-type current bistability at low temperature. 6 In this report, we concentrate on the dependence of the EL on the boron implantation dose and the lattice temperature. The strong correlation between the temperature dependence of the EL intensity from the band edge recombination and from bound excitons provides strong evidence that the release of electron-hole pairs from the excitonic traps to the valence and conduction band play an important role in the anomalous temperature dependence and high efficiency of the diodes.…”

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confidence: 99%

Origin of anomalous temperature dependence and high efficiency of silicon light-emitting diodes

Sun

Dekorsy

Skorupa

et al. 2003

Applied Physics Letters

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Efficient electroluminescence with power efficiency up to 0.12% is observed from silicon pn diodes prepared by boron implantation with boron concentrations above the solubility limit at the postimplantation annealing temperature. The electroluminescence spectra exhibit a transition from two bound-exciton bands towards the free electron-hole pair recombination with an anomalous increase in the total intensity with increasing temperature. The implantation dose and temperature dependences of the relative peak intensities provide evidence for the relevance of excitonic traps as a supply for free electron-hole pairs and thus for the origin of the enhanced electroluminescence at elevated temperatures. © 2003 American Institute of Physics. ͓DOI: 10.1063/1.1626809͔The implementation of silicon-based optoelectronics requires the realization of light emitters, waveguides, and photodiodes compatible with standard silicon processing technology. 1 Light emitters, such as silicon nanoclusters, Erdoped Si-rich SiO 2 , SiGe quantum dots, and silicon pn junctions are presently considered as potential light sources. 2 The latter ones are especially attractive, since they are fully compatible with silicon ultralarge-scale integration technology including low operation voltages. Although bulk silicon, being an indirect semiconductor with inefficient radiative recombination, has been neglected for this purpose for a long time, significant improvements in the electroluminescence ͑EL͒ efficiency from bulk silicon pn diodes have been reported recently. 3,4 The main concept for improving the light emission from silicon is based on a decrease of nonradiative decay channels possibly with carrier confinement in the active region of the device. Green et al. 3 employed surface texturing in combination with efficient surface passivation of high-purity float-zone silicon to improve the light extraction from the pn junction. Ng et al. 4 prepared silicon lightemitting diodes by high boron-dose implantation for the p-type doping in silicon pn junctions. They explained the increased EL efficiency by carrier confinement introduced by dislocation loops formed during implantation, where the strain-induced potential at dislocations loops prevents carriers from diffusing to nonradiative channels, thus leading to a strong band edge electron-hole recombination. Similar high EL efficiency was also reported in silicon p ϩ n junctions prepared by thermal diffusion of high boron concentrations (3 ϫ10 19 cm Ϫ3 ) in the surface layer. 5 All these pn diodes with highly boron-doped surface layers have in common the interesting feature of an anomalous increase in EL efficiency with temperature, which is in stark contrast to the conventional behavior of photoluminescence from bulk silicon. A study of this anomalous temperature dependence is essential for the understanding of the enhancement of the EL with increased boron doses. However, up to now no detailed experimental investigation has been reported for clarifying the origin of the anomalous temperature depende...

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“…3. The same model allows us to accurately describe the EL vs current behavior at all temperatures as well as the current-voltage characteristic, which exhibits an S-shaped bistability at low temperature [24].…”

Section: Boron Implanted Si Light Emitting Pn Diodesmentioning

confidence: 99%

Efficient silicon based light emitters

Helm¹,

Sun²,

Potfajova³

et al. 2005

Microelectronics Journal

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Recent progress on electrically driven silicon based light emitters is reviewed, with emphasis on our work on light emitting pn diodes (LED) and MOS devices doped with rare-earth elements. The LEDs were fabricated by high-dose boron implantation, producing nanoscale modifications in the material. The electroluminescence (EL) efficiency increases with temperature, reaching 0.1% (wall plug efficiency) at room temperature for optimized conditions. Such devices were integrated into a microcavity. In the MOS devices, the oxide was implanted with various rare-earth elements, resulting in strong EL in the visible (Tb) and ultraviolet (Gd). External quantum efficiencies in excess of 10% are reported. q

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Bound-exciton-induced current bistability in a silicon light-emitting diode

Cited by 7 publications

References 17 publications

Light-emitting silicon pn diodes

Light-emitting silicon pn diodes

Origin of anomalous temperature dependence and high efficiency of silicon light-emitting diodes

Efficient silicon based light emitters

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