Silicon light‐emitting diodes based on dislocation‐related luminescence

The direct bonding of Si wafers reproducibly forms dislocation networks (DN) with a microscopic structure defined by the mutual crystallographic orientation between the pair of wafers used for the bonding procedure. This allows studying the electrical and optical properties of specific dislocations. In the present work three different DN structures were investigated using transmission electron microscopy (TEM), photoluminescence (PL) and deep level transient spectroscopy (DLTS). The results show close correlation between the structural, electrical and optical properties of dislocations and opens a possibility to identify structural peculiarities of the dislocations responsible for the high intensity of photoluminescence. Namely, the obtained results suggest that PL at ∼0.8 eV is related to screw dislocations in DN. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Section: Contributed Articlementioning

confidence: 99%

Correlation of electrical and luminescence properties of a dislocation network with its microscopic structure

Mchedlidze

Wilhelm

Arguirov

et al. 2009

“…However, the energy levels that form the D1 and D2 lines are still under discussion. Recent models [22,23] suppose that the D1 line is a result of carrier transition between two, relatively deep and relatively shallow energy levels in Si bandgap. If this model is true, the temperature dependence of the EL intensity -EL(T) -should exhibit two activation energies relevant to the energy levels.…”

Section: Contributedmentioning

confidence: 99%

Silicon based IR light emitters

Kittler

Mchedlidze

Arguirov

et al. 2009

A new concept for Si‐based light emitting diodes (LED) capable of emitting at 1.5 μm is proposed. It utilizes D‐band radiation from dislocations in Si. Whether a dislocation network created in a reproducible manner by Si wafer direct bonding or dislocation loops produced by Si ion implantation are employed. It is also stated that dislocation loops do not lead to the strong band‐to‐band electroluminescence at 1.1 μm of p‐n diodes, as it was predicted in the literature. A MOS‐LED (Fig. A) and p‐n LEDs emitting at 1.5 μm are demonstrated by the authors. The maximum efficiency that could be achieved at room temperature is close to 1%. Levels in the bandgap which are probably involved in the formation of the D1‐line at 1.5 μm are revealed. Moreover, the observation of the Stark effect for the D1‐line is reported. Namely, a red/blue‐shift of peak position was observed in electro‐ and photo‐luminescence when the electric field in the p‐n LED was increased/lowered. This effect may allow realization of a novel Si‐based light emitter with electric field modulated emission wavelength. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

“…The defect luminescence in such samples is attributed to the introduced dislocations and named D1-4. The most common spectroscopic feature is D1 with luminescence energies ranging from 0.77-0.81eV [2][3][4].…”

Section: Spectroscopymentioning

confidence: 99%

Defect luminescence at grain boundaries in multicrystalline silicon

Dreckschmidt

Möller

2011

Multicrystalline silicon is characterised by extended defects like dislocations and grain boundaries. Grain boundaries in this material can show radiative recombination in the near infrared (NIR) region even at room temperature (Dreckschmidt et al., Proc. 23rd European Photovoltaic Solar Energy Conference, Valencia, Spain, 2008, p. 407. [1]). Here we present results of further investigations by the electroluminescence method regarding these phenomena. It turned out that carrier recombination at these centres is negligible. From temperature dependent measurements activation energies of the different centres were determined. Defect schemes for the grain boundary luminescence are proposed (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)