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Proceedings ArticleDOI

Free carrier absorption in Sn based Group-IV alloys

01 Dec 2012-pp 1-4
Abstract: The free carrier absorptions in strained Ge, relaxed GeSn and strained GeSn are estimated considering different scattering mechanisms, namely, acoustic phonon, non polar optical phonon and intervalley phonon scatterings. The change in absorption coefficient for different Sn concentration in the alloys is also reported.
Topics: Free carrier absorption (61%), Phonon (54%), Scattering (51%)
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Journal Article
Abstract: The silicon chip has been the mainstay of the electronics industry for the last 40 years and has revolutionized the way the world operates. Today, a silicon chip the size of a fingernail contains nearly 1 billion transistors and has the computing power that only a decade ago would take up an entire room of servers. As the relentless pursuit of Moore's law continues, and Internet-based communication continues to grow, the bandwidth demands needed to feed these devices will continue to increase and push the limits of copper-based signaling technologies. These signaling limitations will necessitate optical-based solutions. However, any optical solution must be based on low-cost technologies if it is to be applied to the mass market. Silicon photonics, mainly based on SOI technology, has recently attracted a great deal of attention. Recent advances and breakthroughs in silicon photonic device performance have shown that silicon can be considered a material onto which one can build optical devices. While significant efforts are needed to improve device performance and commercialize these technologies, progress is moving at a rapid rate. More research in the area of integration, both photonic and electronic, is needed. The future is looking bright. Silicon photonics could provide low-cost opto-electronic solutions for applications ranging from telecommunications down to chip-to-chip interconnects, as well as emerging areas such as optical sensing technology and biomedical applications. The ability to utilize existing CMOS infrastructure and manufacture these silicon photonic devices in the same facilities that today produce electronics could enable low-cost optical devices, and in the future, revolutionize optical communications

1,419 citations


Book
05 Mar 2004-
Abstract: About the Authors.Foreword.Acknowledgements.1. Fundamentals.2. The Basics of Guided Waves.3. Characteristics of Optical Fibres for Communications.4. Silicon-on-Insulator (SOI) Photonics.5. Fabrication of Silicon Waveguide Devices.6. A Selection of Photonic Devices.7. Polarisation-dependent Losses: Issues for Consideration.8. Prospects for Silicon Light-emitting Devices.Index.

492 citations


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  • ...Over the last 10-15 years some significant milestones have been achieved [2-4]....

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MonographDOI
23 Jan 2003-
Abstract: 1 INTRODUCTION 2 CLASSICAL THEORY OF OPTICAL PROCESSES 3 PHOTONS 4 ELECTRON BAND STRUCTURE AND ITS MODIFICATIONS 5 INTERBAND AND IMPURITY ABSORPTIONS 6 EXCITONIC ABSORPTION 7 ABSORPTION AND REFRACTION IN AN ELECTRIC FIELD 8 INTERBAND MAGNETO-OPTICAL EFFECTS 9 FREE CARRIER PROCESSES 10 RECOMBINATION PROCESSES 11 INTRODUCTION TO TWO-DIMENSIONAL SYSTEMS 12 OPTICAL PROCESSES IN QUANTUM WELLS 13 EXCITONS AND IMPURITIES IN QUANTUM WELLS 14 OPTICAL PROCESSES IN QUANTUM WIRES AND DOTS 15 SUPERLATTICES 16 STRAINED LAYERS 17 EFFECTS OF ELECTRIC FIELD ON LOW DIMENSIONAL SYSTEMS

277 citations


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  • ...But the weakest point of silicon is that proper light emitters and modulators cannot be realized by using it due to its indirect nature of the band gap [1]....

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Journal ArticleDOI
Abstract: Alloys of silicon (Si), germanium (Ge) and tin (Sn) are continuously attracting research attention as possible direct band gap semiconductors with prospective applications in optoelectronics. The direct gap property may be brought about by the alloy composition alone or combined with the influence of strain, when an alloy layer is grown on a virtual substrate of different compositions. In search for direct gap materials, the electronic structure of relaxed or strained Ge1−xSnx and Si1−xSnx alloys, and of strained Ge grown on relaxed Ge1−x−ySixSny, was calculated by the self-consistent pseudo-potential plane wave method, within the mixed-atom supercell model of alloys, which was found to offer a much better accuracy than the virtual crystal approximation. Expressions are given for the direct and indirect band gaps in relaxed Ge1−xSnx, strained Ge grown on relaxed SixGe1−x−ySny and strained Ge1−xSnx grown on a relaxed Ge1−ySny substrate, and these constitute the criteria for achieving a (finite) direct band gap semiconductor. Roughly speaking, good-size (up to ~0.5 eV) direct gap materials are achievable by subjecting Ge or Ge1−xSnx alloy layers to an intermediately large tensile strain, but not excessive because this would result in a small or zero direct gap (detailed criteria are given in the text). Unstrained Ge1−xSnx bulk becomes a direct gap material for Sn content of >17%, but offers only smaller values of the direct gap, typically ≤0.2 eV. On the other hand, relaxed SnxSi1−x alloys do not show a finite direct band gap.

184 citations


9


"Free carrier absorption in Sn based..." refers background in this paper

  • ...Recently some novel ideas have been put forward [5-11] in the band structure engineering by using alloys of Si and Ge with Sn....

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Journal ArticleDOI
Abstract: The electronic properties of Ge∕Ge1−x−ySixSny strained-layer heterostructures are predicted theoretically It is found that a lattice-matched system with fully strained Ge layers and relaxed Ge1−x−ySixSny alloys can have a direct fundamental bandgap with spatial localization in the Ge layers (type I) The Si and Sn concentrations for which such a direct bandgap obtains are close to those that have already been experimentally demonstrated [M Bauer, C Ritter, P A Crozier, J Ren, J Menendez, G Wolf, and J Kouvetakis, Appl Phys Lett 83, 2163 (2003)] The required level of tensile strain in the Ge layers is compatible with Si–Ge technology The predicted direct bandgap values are as high as 06eV

166 citations