J. Appl. Cryst.の発刊に際して

This paper summarizes some of the essential aspects of silicon-nanowire growth and of their electrical properties. In the first part, a brief description of the different growth techniques is given, though the general focus of this work is on chemical vapor deposition of silicon nanowires. The advantages and disadvantages of the different catalyst materials for silicon-wire growth are discussed at length. Thereafter, in the second part, three thermodynamic aspects of silicon-wire growth via the vapor–liquid–solid mechanism are presented and discussed. These are the expansion of the base of epitaxially grown Si wires, a stability criterion regarding the surface tension of the catalyst droplet, and the consequences of the Gibbs–Thomson effect for the silicon wire growth velocity. The third part is dedicated to the electrical properties of silicon nanowires. First, different silicon nanowire doping techniques are discussed. Attention is then focused on the diameter dependence of dopant ionization and the influence of interface trap states on the charge carrier density in silicon nanowires. It is concluded by a section on charge carrier mobility and mobility measurements.

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Silicon Nanowires: A Review on Aspects of their Growth and their Electrical Properties

A central goal in quantum optics and quantum information science is the development of quantum networks to generate entanglement between distributed quantum memories. Experimental progress relies on the quality and efficiency of the light–matter quantum interface connecting the quantum states of photons to internal states of quantum emitters. Quantum emitters in solids, which have properties resembling those of atoms and ions, offer an opportunity for realizing light–matter quantum interfaces in scalable and compact hardware. These quantum emitters require a material platform that enables stable spin and optical properties, as well as a robust manufacturing of quantum photonic circuits. Because no emitter system is yet perfect and different applications may require different properties, several light–matter quantum interfaces are being developed in various platforms. This Review highlights the progress in three leading material platforms: diamond, silicon carbide and atomically thin semiconductors. Atom-like quantum emitters in solids have emerged as promising building blocks for quantum information processing. In this Review, recent advances in three leading material platforms—diamond, silicon carbide and atomically thin semiconductors—are summarized, with a focus on applications in quantum networks

Material platforms for spin-based photonic quantum technologies

Synthesis and applications of one-dimensional semiconductors

Recent progress in synthesis, properties and potential applications of SiC nanomaterials

Odd electron diffraction patterns (EDPs) have been obtained by transmission electron microscopy (TEM) on silicon nanowires grown via the vapour–liquid–solid method and on silicon thin films deposited by electron beam evaporation. Many explanations have been given in the past, without consensus among the scientific community: size artifacts, twinning artifacts or, more widely accepted, the existence of new hexagonal Si phases. In order to resolve this issue, the microstructures of Si nanowires and Si thin films have been characterized by TEM, high-resolution transmission electron microscopy (HRTEM) and high-resolution scanning transmission electron microscopy. Despite the differences in the geometries and elaboration processes, the EDPs of the materials show great similarities. The different hypotheses reported in the literature have been investigated. It was found that the positions of the diffraction spots in the EDPs could be reproduced by simulating a hexagonal structure with c/a = 12(2/3)1/2, but the intensities in many EDPs remained unexplained. Finally, it was established that all the experimental data, i.e. EDPs and HRTEM images, agree with a classical cubic silicon structure containing two microstructural defects: (i) overlapping Σ3 microtwins which induce extra spots by double diffraction, and (ii) nanotwins which induce extra spots as a result of streaking effects. It is concluded that there is no hexagonal phase in the Si nanowires and the Si thin films presented in this work.

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Odd electron diffraction patterns in silicon nanowires and silicon thin films explained by microtwins and nanotwins.

In this paper the effect of varying temperature, pressure and chemical precursors on the vapour–liquid–solid (VLS) growth of silicon nanowires (Si NWs) have been investigated. Some aspects of nucleation and growth mechanisms are discussed. Control on Si NW morphology by varying the choice of gaseous precursor (silane or dichlorosilane) at elevated temperatures is reported.

Growth parameters and shape specific synthesis of silicon nanowires by the VLS method

Towards the growth of stoichiometric chromia on pure chromium by the control of temperature and oxygen partial pressure

Ti and TiN thin films (50–140 nm thick) are grown by dc reactive magnetron sputtering PVD in an inverted cylindrical magnetron (ICM) thanks to an original industrial process corresponding to a continuous reactive deposition on moving stainless steel wires Thin films are fully characterized by X-ray Photoelectron Spectroscopy, Transmission Electron Microscopy coupled with Energy Dispersive Spectroscopy and Orientation Phase Mapping The stoichiometry of TiN is adjusted thanks to N2 flow At the beginning of poisoned mode, golden stoichiometric TiN thin films are obtained In the metallic mode, greyish TiNx films are grown whereas at higher N2 flow, TiNxOy films are synthetized with preferential O incorporation instead of N enrichment Grain orientation maps reveal that Ti and TiN thin films are highly polycrystalline: Ti films have an equiaxis morphology whereas TiN thin films have a tendency to present 〈111〉 columnar grains with 〈001〉 oriented grains at the nucleation step Finally, a low temperature of growth (of about 350 °C and

Titanium and titanium nitride thin films grown by dc reactive magnetron sputtering Physical Vapor Deposition in a continuous mode on stainless steel wires: Chemical, morphological and structural investigations

Stress-induced leakage current (SILC) is studied in 10 nm HfO2 metal-insulator-metal capacitors. Three regimes are observed in the current-time characteristics, namely, (1) an absorption current, (2) a quasi linear increase of current with time (SILC), and (3) thermal breakdown. Magnitude of SILC is strongly correlated to the nature of the cathode (being large for TiN and weak for Pt and Au), showing that SILC is governed by electron injection. Recovery is observed when short-circuiting the samples, pointing out that SILC is a reversible phenomenon. Desorption current and SILC are not correlated, which indicates that different defects control the absorption current and SILC. SILC is ascribed to the generation of oxygen vacancies upon hot electron injection, while recovery is ascribed to the recombination of oxygen ions with vacancies. In the SILC regime, the current varies as Ktn (n = 1.15 at room temperature). Bias and temperature dependence of K and n are studied. The dependence of K on bias can be desc...

Laurence Latu-Romain

Papers

Odd electron diffraction patterns in silicon nanowires and silicon thin films explained by microtwins and nanotwins.

Growth parameters and shape specific synthesis of silicon nanowires by the VLS method

Towards the growth of stoichiometric chromia on pure chromium by the control of temperature and oxygen partial pressure

Titanium and titanium nitride thin films grown by dc reactive magnetron sputtering Physical Vapor Deposition in a continuous mode on stainless steel wires: Chemical, morphological and structural investigations

Stress-induced leakage current and trap generation in HfO2 thin films