Search query: structure of hexagonal SiGe

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abstract: Silicon crystallized in the usual cubic (diamond) lattice structure has dominated the electronics industry for more than half a century. However, cubic silicon (Si) germanium (Ge) and SiGe alloys are all indirect bandgap semiconductors that cannot emit light efficiently. The goal 1 of achieving efficient light emission from group IV materials in silicon technology has been elusive for decades 2 6 Here we demonstrate efficient light emission from direct bandgap hexagonal Ge and SiGe alloys. We measure a sub nanosecond, temperature insensitive radiative recombination lifetime and observe an emission yield similar to that of direct bandgap group III V semiconductors. Moreover, we demonstrate that, by controlling the composition of the hexagonal SiGe alloy, the emission wavelength can be continuously tuned over a broad range, while preserving the direct bandgap. Our experimental findings are in excellent quantitative agreement with ab initio theory. Hexagonal SiGe embodies an ideal material system in which to combine electronic and optoelectronic functionalities on a single chip, opening the way towards integrated device concepts and information processing technologies. A hexagonal (rather than cubic) alloy of silicon and germanium that has a direct (rather than indirect) bandgap emits light efficiently across a range of wavelengths, enabling electronic and optoelectronic functionalities to be combined on a single chip.
author_names: Elham M T Fadaly

Alain Dijkstra

Jens Rene Suckert

Dorian Ziss

Marvin A J van Tilburg

Chenyang Mao

Yizhen Ren

Victor T van Lange

Ksenia Korzun

Sebastian Kolling

Marcel A Verheijen

David Busse

Claudia Rodl

Jurgen Furthmuller

Friedhelm Bechstedt

J Stangl

Jonathan J Finley

Silvana Botti

Jos E M Haverkort

Erik P A M Bakkers
title: Direct bandgap emission from hexagonal Ge and SiGe alloys
venue: Nature
year: 2020

abstract: Silicon Germanium in a hexagonal crystal structure is a candidate material for a direct band gap group IV semiconductor that can be integrated into the CMOS process. It has recently been synthesized as a crystalline shell grown epitaxial around a nanowire core of hexagonal Gallium Phosphide. In order to study the optical properties of this newly generated material and evaluate its potential for building optical devices it is necessary to grow defect and impurity free hexagonal Silicon Germanium. Impurity detection and mapping in nano structures is however challenging as most bulk and thin film characterization methods cannot be used. Here we show that Atom Probe Tomography can be used to map the impurities in hexagonal shells of Silicon Germanium and Silicon. This will allow to optimize growth of hexagonal Silicon Germanium nanocrystals towards impurity free, optically active crystals.
author_names: Sebastian Koelling

Rianne Plantenga

Hakon Ikaros T Hauge

Yizhen Ren

Ang Li

Marcel A Verheijen

Sonia Conesa Boj

Simone Assali

Pm Paul Koenraad

Erik P A M Bakkers
title: Impurity and defect monitoring in hexagonal Si and SiGe nanocrystals
year: 2016

abstract: Contributors. Preface. Gallium Nitride (GaN) (V. Bougrov, et al. Aluminum Nitride (AIN) (Y. Goldberg) Indium Nitride (InN) (A. Zubrilov) Boron Nitride (BN) (S. Rumyantsev, et al. Silicon Carbide (SiC) (Y. Goldberg, et al. Silicon Germanium (Si 1 xGe x) (F. Schaffler) Appendix 1: Basic Physical Constants. Appendix 2: Periodic Table of the Elements. Appendix 3: Rectangular Coordinates for Hexagonal Crystal. Appendix 4: The First Brillouin Zone for Wurtzite Crystal. Appendix 5: Zinc Blende Structure. Appendix 6: The First Brillouin Zone for Zinc Blende Crystal. Additional References.
author_names: M E Levinshtein

Sergey Rumyantsev

Michael S Shur
title: Properties of advanced semiconductor materials GaN, AlN, InN, BN, SiC, SiGe
year: 2001

abstract: In this paper, we study the potentialities of SiGe as a photonic crystal via 2D and 3D simulation of photonic band gap (PBG) at the optical communication wavelength (1.55 mm) according to its chemical composition and a variety of structures geometry. Particularly, we are interested in the hexagonal and Yablonovite structures simulations. Results show that for low germanium content in silicon both the existence and the PBG width are strongly related to the geometrical structure parameters in terms of holes radius and their periodicities.
author_names: M R Beghoul

Hachemi Bouridah

F Meriche

Alexis P A Fischer

A Boudrioua

Noureddine Boutaoui
title: Theoretical Study of Photonic Band Gap in the SiGe
year: 2011

abstract: We present a method to obtain a dense array of well organized SiGe quantum dots in Si nanopillars on a large substrate area by using a PS b PMMA block copolymer template. First, the 2D order of the template is evaluated using a pair correlation function and a bond orientational correlation function. It is shown that the holes contained in the polystyrene template form a structure presenting a hexatic order. This template is then used to fabricate the nanopillars using the following method: in a first step, the copolymer template serves as a deposition mask to fabricate a hexagonal array of Pt dots. In a second step, the Pt dot pattern is transferred to an alternation of Si and SiGe layers on a silicon substrate with an anisotropically etching using Cl2/O2 plasma.
author_names: Karim Aissou

Thierry Baron

M Kogelschatz

Martien I Den Hertog

J -L Rouviere

Jean-Michel Hartmann

Bernard Pelissier
title: Fabrication of Well Organized and Densely Packed Si Nanopillars Containing SiGe Nanodots by Using Block Copolymer Templates
year: 2008

abstract: Summary form only given. Light emission from Si, would allow integration of electronic and optical functionality in the main electronics platform technology, but this has been impossible due to the indirect band gap of Si. This talk will discuss 2 different approaches, using unique properties of nanowires, to realize light emission from Si based compounds. In the first route, the paper focuses on the fabrication of defect free GeSn compounds. The growth mechanism is discussed, the structural properties are investigated by electron microscopy and atom probe tomography and the temperature dependent optical properties are studied. The second route concentrates on Si and Ge with a different crystal structure. Here, crystal structure transfer is employed, in which wurtzite GaP is used as a template to epitaxially grow SiGe compounds with the hexagonal crystal structure. With this method, defect free hexagonal SiGe shells and branches with tunable Ge concentration are gorwn. The structural and optical properties of these new crystal phases will be discussed. The author believes that these new 3 dimensional epitaxial nanostructures have great potential to integrate optical functionality in Si technology.
author_names: Erik P A M Bakkers

Hakon Ikaros T Hauge

A Li

Simone Assali

Alain Dijkstra

R Tucker

Y Ren

Sonia Conesa-Boj

Marcel A Verheijen
title: New opportunities with nanowires
venue: 2016 IEEE Photonics Society Summer Topical Meeting Series (SUM)
year: 2016

abstract: Embodiment of the invention provides a method of forming a nano contact configuration, using the method of manufacturing a semiconductor device which includes a semiconductor device and nanostructures. A method of forming a nanostructure may include forming an insulating layer and a nanostructure formed on the insulating layer. The insulating layer may have a crystalline structure. The insulating layer may include an insulating two dimensional (2D) material. The insulating material may comprise 2D hexagonal boron nitride (h BN) The insulating layer may be formed on the catalyst metal layer. The nanostructures may comprise silicon (Si) germanium (Ge) and at least one of SiGe. Nanostructures may comprise at least one nanowire.
title: A method of forming a nanostructure, a method of manufacturing a semiconductor device and a semiconductor device
year: 2016

abstract: It is disclosed with respect to a semiconductor device including a process for producing a nanostructure and a method for forming a semiconductor device, and applying them nanostructure. Disclosed nanostructure forming method may include the steps of forming the nano structure on the insulating layer forming the insulating layer. The insulating layer can have a crystalline structure. The insulating layer may include a two dimensional insulating material (2D material) The two dimensional insulating material may include a h BN (hexagonal boron nitride) The insulating layer can be formed on the catalyst metal. The nanostructure may include at least one of Si, Ge, and SiGe. The nanostructure may include at least one nanowire (nanowire)
title: Method of forming nanostructure, method of manufacturing semiconductor device using the same and semiconductor device including nanostructure
year: 2015

abstract: The pressure behavior of an amorphous Si rich SiGe alloy (a SixGe1 x, x 0.75) has been investigated up to about 30 GPa, by a combination of Raman spectroscopy, x ray absorption spectroscopy, and x ray diffraction measurements. The trends of microscopic structural properties and of the Raman active phonon modes are presented in the whole pressure range. Nucleation of nanocrystalline alloy particles and metallization have been observed above 12 GPa, with a range of about 2 GPa of coexistence of amorphous and crystalline phases. Transformations from the amorphous tetrahedral, to the crystalline tetragonal (b Sn) and to the simple hexagonal structures have been observed around 13.8 and 21.8 GPa. The recovered sample upon depressurization, below about 4 GPa, shows a local structure similar to the as deposited one. Inhomogeneities of the amorphous texture at the nanometric scale, probed by high resolution transmission electron microscopy, indicate that the recovered amorphous sample has a different ordering at this scale, and therefore the transformations can not be considered fully reversible. The role of disordered grain boundaries at high pressure and the possible presence of a highdensity amorphous phase are discussed.
author_names: F Coppari

Alain Polian

Nicolas Menguy

Angela Trapananti

A Congeduti

Matt Newville

Vitali B Prakapenka

Y Choi

E Principi

Andrea Di Cicco
title: Pressure induced transformations in amorphous Si Ge alloy
year: 2012

abstract: Abstract Cubic lanthanide sesquioxides consisting of cations with an atom radius larger that promethium could be used as a buffer layer for growth of semiconductors with a cubic structure (Ge, GaAs or SiGe) on Si due to the close matching of a lattice constant between the oxides and the semiconductors. However, the oxides have a stable hexagonal structure at temperatures higher than 600 degC, which is typical for the epitaxy process. According to our ab initio density functional theory calculations, energy of molecular unit of hexagonal lanthanum oxide is lower than that of the cubic structure by 127 meV. In this paper, we demonstrate epitaxial stabilization of pseudomorphic cubic structure of lanthanum oxide grown on a cubic template. The oxide layer can serve as a buffer for growth of Ge or GaAs layers on Si substrate. On the other hand, gadolinium oxide, which according to many studies has a stable cubic structure, was grown on hexagonal GaN. The single crystal monoclinic Gd 2 O 3 could be used as a gate dielectric layer for GaN based electronic devices.
author_names: Rytis Dargis

Andrew G Clark

Erdem Arkun

Radek Roucka

Robin Smith

Alexander A Demkov

Michael Lebby
title: Growth and application of epitaxial heterostructures with polymorphous rare earth oxides
year: 2013