Electronic band structure of ultimately thin silicon oxide on Ru(0001)
G. Kremer, J. C. Alvarez-Quiceno, S. Lisi, T. Pierron, C. González Pascual, M. Sicot, B. Kierren, D. Malterre, J. Rault, P. Le Fèvre, F. Bertran, Y. J. Dappe, J… 展开作者
G. Kremer, J. C. Alvarez-Quiceno, S. Lisi, T. Pierron, C. González Pascual, M. Sicot, B. Kierren, D. Malterre, J. Rault, P. Le Fèvre, F. Bertran, Y. J. Dappe, J. Coraux, P. Pochet, Y. Fagot-Revurat
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Main part : 31 pages, 6 figures / Supporting information : 13 pages, 11 figures
Silicon oxide can be formed in a crystalline form, when prepared on a metallic substrate. It is a candidate support catalyst and possibly the ultimately-thin version of a dielectric host material for two-dimensional materials (2D) and heterostructures. We determine the atomic structure and chemical bonding of the ultimately thin version of the oxide, epitaxially grown on Ru(0001). In particular, we establish the existence of two sub-lattices defined by metal-oxygen-silicon bridges involving inequivalent substrate sites. We further discover four electronic bands below Fermi level, at high binding energies, two of them forming a Dirac cone at K point, and two others forming semi-flat bands. While the latter two correspond to hybridized states between the oxide and the metal, the former relate to the topmost silicon-oxygen plane, which is not directly coupled to the substrate. Our analysis is based on high resolution X-ray photoelectron spectroscopy, angle-resolved photoemission spectroscopy, scanning tunneling microscopy, and density functional theory calculations.
Diffusion-reaction in thermal growth of silicon oxide films on Si
在干燥的O2中的Si上的氧化硅膜的热生长被建模为一个动力学系统，假设它基本上是一个扩散反应现象。过去十年的相关研究结果被纳入，作为结构和组成的氧化物/Si界面和O2运输和反应在生长的初始阶段。本模型偏离了成熟的Deal和Grove框架（Deal，B.E. Grove，A. S. General Relationship for the Thermal Oxidation of Silicon，J.Appl.Phys.36，3770-3778（1965）），表明其基本假设、稳态状态以及在尖锐氧化物/Si界面处O2和Si之间的反应仅渐近地获得。实验生长动力学的不同作者，获得了广泛的生长参数被证明崩溃成一个单一的曲线时，这个模型方程的缩放特性进行了探讨。
Computational searching and screening of new functional materials exploiting earth abundant elements can accelerate developments of their energy applications. Based on a state-of-the-art materials search algorithm and ab initio calculations, we demonstrate a recently suggested stable silicon oxide with a layered structure (Si$_{3}$O) as an ideal photovoltaic material. With many-body first-principles approaches, the monolayer and layered bulk of Si$_{3}$O show direct quasiparticle gaps of 1.85 eV and 1.25 eV, respectively, while an optical gap of about 1.2 eV is nearly independent of the number…
We determined the interface state density ($D_{\rm it}$) distributions in the vicinity of the conduction band edge in silicon carbide (SiC) metal-oxide-semiconductor (MOS) structures by reproducing the experimental current-voltage characteristics of MOS field effect transistors (MOSFETs) with numerical calculations. In the calculation, potential distributions and energy sub-bands in the inversion layer were calculated by solving Poisson and Schrödinger equations, respectively. We demonstrate that gate characteristics of the MOSFETs are well described by considering that the interface states ar…
Ferroelectric oxides have attracted much attention due to their wide range of applications, especially in electronic devices such as nonvolatile memories and tunnel junctions. As a result, the monolithic integration of these materials into silicon technology and its nanostructuration to develop alternative cost-effective processes are among the central points in current technology. In this work, we used a chemical route to obtain nanowire thin films of a novel Sr1+δMn8O16 (SMO) hollandite-type manganese oxide on silicon. Scanning transmission electron microscopy combined with crystallographic …
We investigate nanoscale local anodic oxidation (LAO) on hydrogen-intercalated graphene grown by controlled sublimation of silicon carbide (SiC). Scanning probe microscopy (SPM) was used as a lithographic and characterization tool in order to investigate the local properties of the nanofabricated structures. The anomalous thickness observed after the graphene oxidation process is linked to the impact of LAO on the substrate. Micro-Raman spectroscopy was employed to demonstrate the presence of two oxidation regimes depending on the applied bias. We show that partial and total etching of monolay…
Immobilization of polyoxometalates (POMs) onto oxides is relevant to many applications in the fields of catalysis, energy conversion/storage or molecular electronics. Optimization and understanding the molecule/oxide interface is crucial to rationally improve the performance of the final molecular materials. We herein describe the synthesis and covalent grafting of POM hybrids with remote carboxylic acid functions onto flat Si/SiO2 substrates. Special attention has been paid to the characterization of the molecular layer and to the description of the POM anchoring mode at the oxide interface t…
Epitaxial bilayer silicon oxide is a transferable two-dimensional material predicted to be a wide band gap semiconductor, with potential applications for deep UV optoelectronics, or as a building block of van der Waals heterostructures. The prerequisite to any sort of such applications is the knowledge of the electronic band structure, which we unveil using angle-resolved photoemission spectroscopy and rationalise with the help of density functional theory calculations. We discover dispersing bands related to electronic delocalisation within the top and bottom planes of the material, with two …
In this study, we evaluated the sensing performance of silver nanoprism/graphene oxide/silicon nanowires (AgNPr/GO/SiNWs) nanohybrid system for effective detection of organic dye and herbicide residues in freshwater via surface-enhanced Raman scattering (SERS). Homogenous and vertically aligned SiNWs have been successfully synthesized using metal-assisted chemical etching technique by varying the etching time from 10 to 30 min. AgNPr/GO/SiNW hybrids were assembled by spin-coating of GO followed by drop-casting deposition of AgNPr. The microstructures of AgNPr/GO/SiNWs are strongly affected by …
Electrically driven on-chip electron sources that do not need to be heated have been long pursued because the current thermionic electron sources show the problems of high power consumption, slow temporal response, bulky size, etc., but their realization remains challenging. Here we show that a nanogap formed by two electrodes on a silicon oxide substrate functions as an electron-emitting nanodiode after the silicon oxide in the nanogap is electrically switched to a high-resistance conducting state. A nanodiode based on graphene electrodes can be turned on by a voltage of ~7 V in ~100 ns and s…
The mechanism responsible for the emission of clusters from heavy ion irradiated solids is proposed to be thermal spikes. Collision cascade-based theories describe atomic sputtering but cannot explain the consistently observed experimental evidence for significant cluster emission. Statistical thermodynamic arguments for thermal spikes are employed here for qualitative and quantitative estimation of the thermal spike-induced cluster emission from silicon, germanium and zinc oxide. The evolving cascades and spikes in elemental and molecular semiconducting solids are shown to have fractal charac…
Electrical switching and rectifying properties of the metal-VO2-Si structures, on both p-type and n-type silicon, with vanadium dioxide films obtained by an acetylacetonate sol-gel method, are studied. The switching effect is shown to be due to the semiconductor-to-metal phase transition (SMPT) in vanadium dioxide. The shift of the switching threshold voltage, accompanied by the memory effect, in forward bias of the p-Si-VO2 anisotype heterojunction is observed. To explain this effect, a model is proposed which suggests the existence of an additional series resistance associated with a channel…
Muon spin rotation with low-energy muons (LEμSR) is a powerful nuclear method where electrical and magnetic properties of surface-near regions and thin films can be studied on a length scale of $\approx$\SI{200}{\nano\meter}. In this work, we show the potential of utilizing low-energy muons for a depth-resolved characterization of oxide-semiconductor interfaces, i.e. for silicon (Si) and silicon carbide (4H-SiC). Silicon dioxide (SiO$_2$) grown by plasma-enhanced chemical vapor deposition (PECVD) and by thermal oxidation of the SiO$_2$-semiconductor interface are compared with respect to inter…
Compact chromium oxide thin film resistors for use in nanoscale quantum circuits
我们报告的一系列薄氧化铬薄膜的电特性，直流溅射生长，以评估其适用性作为纳米电子学芯片电阻。通过增加氧掺杂的水平，氧化铬膜的室温方块电阻从28 $Ω/ \square$变化到32.6k $Ω/ \square$。研究了在液氦中冷却到4.2K时电阻的变化;在4.2K时，薄层电阻随组分从65 $Ω/ \square$到20 G以上$Ω/ \square$而变化。所有测量的膜在所有测量的温度下显示欧姆行为。对于用于使用硅纳米线进行量子相位滑移测量的片上器件，需要硅纳米线和氧化铬之间的界面。通过表征界面接触电阻，我们发现金中间层是有利的：氧化铬-金界面的比接触电阻率为0.15 m $Ω$ cm $^2$，远低于直接氧化铬-硅界面的值65 m $Ω$ cm $^2$。我们的结论是，这些氧化铬薄膜是适合用于纳米级电路作为高价值的电阻器，与电阻率可调的氧含量。
采用广义梯度近似赝势密度泛函电子结构计算方法研究了氧化硅纳米线。研究了无限长的直线型和锯齿型Si-O链。还优化了由三维周期性重复的Si 4 O 8单元组成的线，但发现这种结构具有有限的稳定性。计算了这些氧化硅纳米线的几何形状、电子结构和赫希菲尔德电荷。结果表明，Si-O链是金属链，而锯齿链和Si_4O_8纳米线是绝缘体。
The study of hexagonal silicon polytypes attracts special attention due to their unique physical properties compared to the traditional cubic phase of Si. Thus, for some hexagonal phases, a significant improvement in the emission properties has been demonstrated. In this work, the luminescent properties of SiO2/Si structures irradiated with Kr+ ions at different doses and annealed at 800 °C have been systematically investigated. For such structures, a photoluminescence line at ~ 1240 nm is observed and associated with the formation of hexagonal 9R-Si phase inclusions. It is found that the vari…
Investigating intrinsic silicon oxide and a lightly doped p-type layer for evolution of tail states and estimating its impact as a passivation layer in a HIT type device
