A5037711268- Nanowire Synthesis and Applications
- Silicon Nanostructures and Photoluminescence
- Gold and Silver Nanoparticles Synthesis and Applications
- Semiconductor materials and devices
- Advancements in Semiconductor Devices and Circuit Design
- Thin-Film Transistor Technologies
- Quantum Dots Synthesis And Properties
- ZnO doping and properties
- Semiconductor materials and interfaces
- Anodic Oxide Films and Nanostructures
- Gas Sensing Nanomaterials and Sensors
- Electron and X-Ray Spectroscopy Techniques
- Nanocluster Synthesis and Applications
- Advanced biosensing and bioanalysis techniques
- Ion-surface interactions and analysis
- Advanced Electron Microscopy Techniques and Applications
- Nonlinear Optical Materials Studies
- Silicon and Solar Cell Technologies
- Electronic and Structural Properties of Oxides
- Surface Roughness and Optical Measurements
- Iron oxide chemistry and applications
- Spectroscopy Techniques in Biomedical and Chemical Research
- nanoparticles nucleation surface interactions
- Bacteriophages and microbial interactions
- Magnetic properties of thin films
Leibniz Institute of Photonic Technology
2015-2024
Albert Einstein College of Medicine
2020
Lomonosov Moscow State University
2012
Leibniz-Institute for New Materials
2004-2012
Max Planck Institute for the Science of Light
2010-2011
Max Planck Society
2011
Max Planck Institute of Microstructure Physics
2006-2010
Fraunhofer Institute for Mechanics of Materials
2010
University of Neuchâtel
2009
Martin Luther University Halle-Wittenberg
2006
Silicon nanowire (SiNW)-based solar cells on glass substrates have been fabricated by wet electroless chemical etching (using silver nitrate and hydrofluoric acid) of 2.7 microm multicrystalline p(+)nn(+) doped silicon layers thereby creating the structure. Low reflectance (<10%, at 300-800 nm) a strong broadband optical absorption (>90% 500 measured. The highest open-circuit voltage (V(oc)) short-circuit current density (J(sc)) for AM1.5 illumination were 450 mV 40 mA/cm(2), respectively...
X-ray photoelectron spectroscopy based on synchrotron radiation was used to investigate the composition of observed SnO2-x/Sn:SiO2-x thin layer grown by organometallic chemical vapour deposition single-crystalline silicon wafer with additional Ar ions etching treatment. Due formation a thermodynamic anomaly during in situ growth, an efficient oxygen exchange between and tin dioxide phases occurs. The present study addresses effect localized surface charging its influence obtained XPS core...
The electrical properties of vertically aligned silicon nanowires doped by ion implantation are studied in this paper a combination electron beam-induced current imaging and two terminal current-voltage measurements. By varying the parameters several process steps, uniform p- n-doping profiles as well p-n junctions along nanowire axis realized. effective doping is demonstrated on single nanowires, measurements show their well-defined rectifying behavior.
Strong room temperature visible (red-orange) photoluminescence (PL) has been observed in silicon nanowires (SiNWs) that were realized by wet chemical etching of heavily (arsenic, As: ${10}^{20}\text{ }{\text{cm}}^{\ensuremath{-}3}$) and lowly doped (boron, B: ${10}^{15}\text{ single crystalline (Si) wafers. Optical characterization these SiNWs PL combined with structural transmission scanning electron microscopy strongly suggest the at results from rough SiNW sidewall structure is composed...
Silicon nanowire (SiNW) ensembles with vertical and zigzag architectures have been realized using wet chemical etching of bulk silicon wafers (p-Si(111) p-Si(100)) a mask silver nanoparticles that are deposited by electroless deposition. The SiNWs is based on subsequent treatments in solutions such as 0.02 M aqueous nitrate (AgNO3) followed 5 hydrofluoric acid 30% hydrogen peroxide (H2O2). the Si mediated reduction surface parallel oxidation thereby forming SiO2 which dissolved HF...
Evaluation of cytotoxicity, photoluminescence, bio-imaging, and sonosensitizing properties silicon nanoparticles (SiNPs) prepared by ultrasound grinding porous nanowires (SiNWs) have been investigated. SiNWs were formed metal (silver)-assisted wet chemical etching heavily boron-doped (100)-oriented single crystalline wafers. The aqueous suspensions SiNPs exhibit efficient room temperature photoluminescence (PL) in the spectral region 600 to 1,000 nm that is explained radiative recombination...
Nanoporous silicon oxide templates formed by swift heavy ion tracks technology have been investigated. The influence of the characteristics, such as type ion, energy, stopping power and irradiation fluence on pore properties templates, has studied. Furthermore, process formation chemical etching with hydrofluoric acid thoroughly investigated assessing effect etchant concentration time. outcome this investigation enables us to precise control over resulting geometry nanopores arrays. As a...
High-yield synthesis of germanium nanowires (NWs) and core−shell structures is achieved by the chemical vapor deposition (CVD) dicyclopentadienyl ([Ge(C5H5)2]). The one-dimensional (1D) nanostructures are formed on an iron substrate following a base-growth model in which Fe−Ge epilayer functions as catalytic bed. wire growth selective no catalyst particles observed at tip NWs, contrary to characteristic feature 1D based vapor−liquid−solid (VLS) mechanism. diameter length NWs were ranges...
Two types of electrostatically actuated tensile stages for <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in situ</i> electron microscopy mechanical testing 1-D nanostructures were designed, microfabricated, and tested. Testing was carried out characterization silicon nanowires (SiNWs). The bulk micromachined consist a comb-drive actuator either differential capacitive sensor or clamped-clamped beam force sensor. High-aspect-ratio structures...
We study the structure and optical properties of arrays silicon nanowires (SiNWs) with a mean diameter approximately 100 nm length about 1-25 μm formed on crystalline (c-Si) substrates by using metal-assisted chemical etching in hydrofluoric acid solutions. In middle infrared spectral region, reflectance transmittance SiNW can be described framework an effective medium refractive index 1.3 (porosity, 75%), while strong light scattering for wavelength 0.3 ÷ 1 results decrease total 1%-5%,...
Abstract Herein, it is demonstrated that copper (Cu) nanoparticle‐based surfaces prepared via a wet‐chemical method exhibit considerable enhancement of the Raman signal for monolayer adenine, guanine, riboflavin, 4‐mercaptobenzoic acid, and potassium thiocyanate analytes upon excitation with laser in wavelength range 229–325 nm. The results reveal notable surface‐enhanced scattering (SERS) spectra deep UV(ultraviolet) spectral ranges, phenomenon previously unreported Cu‐based surfaces,...
Iron(III) tert-butoxide, [Fe(OtBu)3]2, was used as a single source for iron and oxygen to obtain nanocrystalline hematite (Fe2O3) or magnetite (Fe3O4) films by low-pressure (LP) CVD. The decomposition profile of the molecular precursor crystallization temperature oxide were derived from thermogravimetry/differential thermal analysis (TG/DTA). substrate found markedly influence morphology Fe/O stoichiometry in deposited films. morphological features phase identification grown obtained...
Surface-enhanced Raman spectroscopy (SERS) is a promising optical method for analyzing molecular samples of various nature. Most SERS studies are an applied nature, indicating serious potential their application in analytical practice. Dendritelike nanostructures have great SERS, but the lack predictable production significantly limits implementation. In this paper, controllably obtaining spatially separated, self-organized, and highly-branched silver dendrites via template synthesis pores...
We show that hemispherical gold droplets on top of silicon nanowires when grown by the vapor−liquid−solid (VLS) mechanism, can produce a significant enhancement Raman scattered signals. Signal for few or even just single is demonstrated analyzing enhanced signature malachite green molecules. For this experiment, trenches (∼800 nm wide) were etched in silicon-on-insulator (SOI) wafer along 〈110〉 crystallographic directions constitute sidewalls ({110} surfaces) suitable growth 〈111〉 with...
Silicon nanowires grown by the vapour-liquid-solid growth mechanism with gold as catalyst show caps approximately 50-400 nm in diameter an almost ideal hemispherical shape atop a silicon column. These are extremely well suited for exploiting tip or surface enhanced Raman scattering effects since they assume right size on nanometre scale and reproducible, shape. On attaching nanowire cap to atomic force microscopy (AFM) tip, signal enhancement nanoparticle can be used spatially resolve...
New approaches for visualisation of silicon nanoparticles (SiNPs) in cancer cells are realised by means the linear and nonlinear optics vitro. Aqueous colloidal solutions SiNPs with sizes about 10–40 nm obtained ultrasound grinding nanowires were introduced into breast (MCF-7 cell line). Further, time-varying enclosed structures visualised high-resolution structured illumination microscopy (HR-SIM) micro-Raman spectroscopy. Additionally, optical methods two-photon excited fluorescence (TPEF)...