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Dmitry Yurievich Zemlyanov

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Full-Text Articles in Nanoscience and Nanotechnology

Electrodeposition Study Of Odn : Swcnt Hybrids On Gold Substrates, Roya Lahiji, Bridget Dolash, Jennifer Mcdonald, Dmitry Zemlyanov, Donald Bergstrom, R. Reifenberger Mar 2012

Electrodeposition Study Of Odn : Swcnt Hybrids On Gold Substrates, Roya Lahiji, Bridget Dolash, Jennifer Mcdonald, Dmitry Zemlyanov, Donald Bergstrom, R. Reifenberger

Dmitry Yurievich Zemlyanov

Sonication of short single-stranded DNA (oligodeoxyribonucleotide; ODN) with Single-Walled Carbon Nanotubes (SWCNTs) greatly facilitates the dispersion of SWCNTs from entangled ropes in an aqueous solution, creating ODN:SWCNT hybrids. Electrodeposition has been investigated to determine if well-dispersed ODN :SWCNT hybrids on a metal substrate can be created. Preliminary studies indicate that electrodeposition using an Au substrate held at +0.5 V produces ODN: SWCNT hybrids that are uniformly deposited across the Au substrate. This result can be compared to samples produced by drop casting and evaporation techniques which yield a thick tangled mat of ODN :SWCNT hybrids across the substrate ...


Controllable Surface Expression Of Bioactive Peptides Incorporated Into A Silica Thin Film Matrix, Sabrina Jedlicka, Jenna Rickus, Dmitry Zemlyanov Mar 2012

Controllable Surface Expression Of Bioactive Peptides Incorporated Into A Silica Thin Film Matrix, Sabrina Jedlicka, Jenna Rickus, Dmitry Zemlyanov

Dmitry Yurievich Zemlyanov

Mammalian cell culture platforms often require biomolecular modification to enhance cell adhesion and proliferation, Often, these modifications are performed using self-assembled monolayers or whole protein coatings, Such its collagen. These protocols are inherently useful but generally suffer from repeatability. Undesirable conditions during self-assembly can lead to complications in the surface presentation of the biological ligands. Whole proteins are often unstable and derived from animal sources, making them less attractive for tissue engineering applications. As the biological effect of the material often depends strongly on the concentration of the integrated ligand(s), any complication due to synthesis or stability can lead ...


Dissociation Of Water On The Surface Of Organic Salts Studied By X-Ray Photoelectron Spectroscopy, Peter Guerrieri, Dmitry Zemlyanov, Lynn Taylor Mar 2012

Dissociation Of Water On The Surface Of Organic Salts Studied By X-Ray Photoelectron Spectroscopy, Peter Guerrieri, Dmitry Zemlyanov, Lynn Taylor

Dmitry Yurievich Zemlyanov

Water dissociation has important implications for numerous chemical processes. Although extensively studied on metals and to some extent on inorganic salts, this phenomenon has not yet been shown to occur on organic surfaces. Herein, the ability of two crystalline organic hydrochloride salts to induce water dissociation at their surface was demonstrated. Using a modified X-ray photoelectron spectroscopy setup, the oxygen lacking crystalline organic salts were exposed to high water vapor pressures within an environment sealed from ambient air. Thus, the O(1s) peak resulting from exposure to water vapor at room temperature could be unambiguously assigned to dissociated water, a ...


Assessment Of The Passivation Capabilities Of Two Different Covalent Chemical Modifications On Gap(100), David Richards, Dmitry Zemlyanov, Albena Ivanisevic Mar 2012

Assessment Of The Passivation Capabilities Of Two Different Covalent Chemical Modifications On Gap(100), David Richards, Dmitry Zemlyanov, Albena Ivanisevic

Dmitry Yurievich Zemlyanov

Gallium phosphide is a semiconductor material that can be used for the fabrication of optoelectronic devices. The report compares the ability of two similar organic molecules to form covalent bonds with the GaP(100) surface. Undecenoic acid (UDA) is a terminal alkene that can potentially form Ga-C bonds, and mercaptoundecanoic acid (MUA) is a thiol that can be used to generate Ga-S bonds. The chemical passivation capabilities of the functionalized surfaces exposed to different media were investigated by contact angle measurements, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Toxicity levels, which are important for sensing applications. were evaluated ...


Dna Immobilization On Gap(100) Investigated By Kelvin Probe Force Microscopy, David Richards, Dmitry Zemlyanov, Rafay Asrar, Yena Chokshi, Emily Cook, Thomas Hinton, Xinran Lu, Viet Nguyen, Neil Patel, Jonathan Usher, Sriram Vaidyanathan, David Yeung, Albena Ivanisevic Mar 2012

Dna Immobilization On Gap(100) Investigated By Kelvin Probe Force Microscopy, David Richards, Dmitry Zemlyanov, Rafay Asrar, Yena Chokshi, Emily Cook, Thomas Hinton, Xinran Lu, Viet Nguyen, Neil Patel, Jonathan Usher, Sriram Vaidyanathan, David Yeung, Albena Ivanisevic

Dmitry Yurievich Zemlyanov

Understanding changes in the properties of semiconductor materials after immobilization of biomolecules on the surface is essential for the fabrication of well-tuned and programmable devices. The work examines changes in the properties of gallium phosphide (GaP) after modification with an organic linker, a single stranded DNA, and its complementary strand. We investigated changes in surface potential with Kelvin probe force microscopy (KPFM). Analysis revealed that a more ordered adlayer of ssDNA was present when a lower concentration of linker molecule was used. KPFM data combined with coverage data obtained from X-ray photoelectron spectroscopy (XPS) further confirmed this result. Successful hybridization ...


Insights Into Few-Layer Epitaxial Graphene Growth On 4h-Sic(000(1)Over-Bar Substrates From Stm Studies, Laura B. Biedermann, Michael L. Bolen, Michael A. Capano, Dmitry Zemlyanov, R. Reifenberger Mar 2012

Insights Into Few-Layer Epitaxial Graphene Growth On 4h-Sic(000(1)Over-Bar Substrates From Stm Studies, Laura B. Biedermann, Michael L. Bolen, Michael A. Capano, Dmitry Zemlyanov, R. Reifenberger

Dmitry Yurievich Zemlyanov

Epitaxial carbon was grown by heating (000 (1) over bar) silicon carbide (SiC) to high temperatures (1450-1600 degrees C) in vacuum. A continuous graphene surface layer was formed at temperatures above 1475 degrees C. X-ray photo-electron spectroscopy (XPS) and scanning tunneling microscopy (STM) were extensively used to characterize the quality of the few-layer graphene (FLG) surface. The XPS studies were useful in confirming the graphitic composition and measuring the thickness of the FLG samples. STM studies revealed a wide variety of nanometer-scale features that include sharp carbon-rich ridges, moire superlattices, one-dimensional line defects, and grain boundaries. By imaging these features ...


Large-Scale Graphitic Thin Films Synthesized On Ni And Transferred To Insulators: Structural And Electronic Properties, Helin Cao, Qingkai Yu, Robert Colby, Deepak Pandey, C S. Park, Jie Lian, Dmitry Zemlyanov, Isaac Childres, V. P. Drachev, E A. Stach, Muhammad Hussain, Hao Li, Steven S. Pei, Yong P. Chen Mar 2012

Large-Scale Graphitic Thin Films Synthesized On Ni And Transferred To Insulators: Structural And Electronic Properties, Helin Cao, Qingkai Yu, Robert Colby, Deepak Pandey, C S. Park, Jie Lian, Dmitry Zemlyanov, Isaac Childres, V. P. Drachev, E A. Stach, Muhammad Hussain, Hao Li, Steven S. Pei, Yong P. Chen

Dmitry Yurievich Zemlyanov

We present a comprehensive study of the structural and electronic properties of ultrathin films containing graphene layers synthesized by chemical vapor deposition based surface segregation on polycrystalline Ni foils then transferred onto insulating SiO2/Si substrates. Films of size up to several mm's have been synthesized. Structural characterizations by atomic force microscopy, scanning tunneling microscopy, cross-sectional transmission electron microscopy (XTEM), and Raman spectroscopy confirm that such large-scale graphitic thin films (GTF) contain both thick graphite regions and thin regions of few-layer graphene. The films also contain many wrinkles, with sharply-bent tips and dislocations revealed by XTEM, yielding insights on ...


Mixed Adlayer Of Alkanethiol And Peptide On Gaas(100): Quantitative Characterization By X-Ray Photoelectron Spectroscopy, Heeyeon P. Wampler, Dmitry Zemlyanov, Kangho Lee, David B. Janes, Albena Ivanisevic Mar 2012

Mixed Adlayer Of Alkanethiol And Peptide On Gaas(100): Quantitative Characterization By X-Ray Photoelectron Spectroscopy, Heeyeon P. Wampler, Dmitry Zemlyanov, Kangho Lee, David B. Janes, Albena Ivanisevic

Dmitry Yurievich Zemlyanov

Homogeneous and mixed adlayers composed of an alkanethiol (1-octddecanethiol, ODT) and a peptide (CGISYGRKKRRQRRR) on GaAs(100) were formed in two different solvent systems: phosphate-buffered saline (PBS) and N,N-dimethylformamide (DMF). The chemical composition of each adlayer was characterized by X-ray photoelectron spectroscopy (XPS). The data showed that the makeup of the adlayer and its stability largely depends on the solvent used. Angle-resolved XPS also revealed that the adlayer thickness and tilt angles were different from values obtained from ellipsometry measurements and vastly varied between the two solvents used. The coverage data extracted from the XPS measurements indicated that homogeneous ...


Electron Spectroscopy A New Window Opens, Dmitry Zemlyanov Mar 2012

Electron Spectroscopy A New Window Opens, Dmitry Zemlyanov

Dmitry Yurievich Zemlyanov

No abstract provided.


Assembly Of Dithiocarbamate-Anchored Monolayers On Gold Surfaces In Aqueous Solutions, Heng Zhu, Donna Coleman, Christopher Dehen, Iris Geisler, Dmitry Zemlyanov, Jean Chmielewski, Garth Simpson, Alexander Wei Mar 2012

Assembly Of Dithiocarbamate-Anchored Monolayers On Gold Surfaces In Aqueous Solutions, Heng Zhu, Donna Coleman, Christopher Dehen, Iris Geisler, Dmitry Zemlyanov, Jean Chmielewski, Garth Simpson, Alexander Wei

Dmitry Yurievich Zemlyanov

Dithiocarbamates (DTCs) can be formed by the in situ condensation of polar alkylamines with CS2, and assembled into dithiocarbamate-anchored monolayers (DAMs) on Au substrates in aqueous solutions. Primary and secondary amines can both be used to prepare DTCs, but have significant differences in their reactivities and product stabilities. Ultraviolet absorption spectroscopy provides a convenient method for monitoring in situ DTC formation as well as the formation of potential byproducts. The kinetics of DAM assembly on An substrates as measured by second harmonic generation (SHG) indicated first-order rate processes and saturation coverages similar to those of alkanethiols on Au. However, the ...


Afm Study Of Ridges In Few-Layer Epitaxial Graphene Grown On The Carbon-Face Of 4h-Sic(000(1)Over-Bar), Gyan Prakash, Michael Capano, Michael Bolen, Dmitry Zemlyanov, R. Reifenberger Mar 2012

Afm Study Of Ridges In Few-Layer Epitaxial Graphene Grown On The Carbon-Face Of 4h-Sic(000(1)Over-Bar), Gyan Prakash, Michael Capano, Michael Bolen, Dmitry Zemlyanov, R. Reifenberger

Dmitry Yurievich Zemlyanov

A characterization of the graphitic overlayer that forms on 4H-SiC(000 (1) over bar) substrates heated for ten minutes to temperatures T > 1350 degrees C under vacuum conditions has been performed. X-ray photoelectron spectroscopy of the C-face reveals the presence of graphitic carbon with a thickness that increases with growth temperature. Parallel atomic force microscope (AFM) studies find a mesh-like network of ridges with high curvature that bound atomically flat, tile-like facets of few-layer graphene (FLG). By imaging the network that develops on FLG, it is possible to map out the regions where the elastic energy is concentrated.


Adsorption Of Amino Acids On Indium Arsenide (100) Surfaces: Assessment Of Passivation Capabilities, John Slavin, Dmitry Zemlyanov, Albena Ivanisevic Mar 2012

Adsorption Of Amino Acids On Indium Arsenide (100) Surfaces: Assessment Of Passivation Capabilities, John Slavin, Dmitry Zemlyanov, Albena Ivanisevic

Dmitry Yurievich Zemlyanov

Angle-Resolved X-ray Photoelectron Spectroscopy (ARXPS) was used to examine amino acid bonding and oxide removal on InAs(100) surfaces. Five amino acids were studied, including cysteine, lysine, aspartic acid, glutamic acid and arginine. Observations on the ability of specific functional groups to prevent oxide formation were made by examining the thickness of oxide films on the functionalize surfaces. Amino acids that possessed more than one functional group having resonance were shown to most effectively affect oxide formation. The influence of these groups on the electronic structure of InAs(100) provides insight into how multifunctional passivation strategies could be beneficial, as ...


Temperature-Induced Modifications Of Pdzn Layers On Pd(111), W Stadlmayr, Ch Rameshan, C Weilach, H Lorenz, M Haevecker, R Blume, T Rocha, D Teschner, A Knop-Gericke, Dmitry Zemlyanov, S Penner, R Schloegl, G Rupprechter, B Kloetzer, N Memmel Mar 2012

Temperature-Induced Modifications Of Pdzn Layers On Pd(111), W Stadlmayr, Ch Rameshan, C Weilach, H Lorenz, M Haevecker, R Blume, T Rocha, D Teschner, A Knop-Gericke, Dmitry Zemlyanov, S Penner, R Schloegl, G Rupprechter, B Kloetzer, N Memmel

Dmitry Yurievich Zemlyanov

Ultrathin PdZn surface alloys on Pd(111) are model systems well-suited for obtaining a microscopic understanding of the mechanisms of Pd/Zn-based catalysis for methanol steam reforming. The temperature-induced compositional and structural changes of these alloy films are investigated in the catalytically relevant temperature range. Heating of multilayer Zn films to 500 K results in the formation of multilayer PdZn alloy films with surface and near-surface composition close to 1:1. In the temperature regime above 550 K the subsurface layers deplete quickly in Zn due to diffusion of Zn atoms into the Pd bulk. In contrast, the composition of ...


Lithography On Gap(100) Surfaces, Rosangelly Flores-Perez, Dmitry Zemlyanov, Albena Ivanisevic Mar 2012

Lithography On Gap(100) Surfaces, Rosangelly Flores-Perez, Dmitry Zemlyanov, Albena Ivanisevic

Dmitry Yurievich Zemlyanov

Two types of lithographic methods were used to modify GaP(1 00) surfaces with commercially available alkanethiol molecules: microcontact printing (mu CP) and "dip-pen" nanolithography (DPN), The patterned surfaces were characterized by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS). The characterization was done in order to understand the quality of each type of pattern, its chemical composition, and the organization of the molecules on the surface. Differences between the two lithographic methods used to do lithography on the GaP(1 00) in this study were dependent on the chosen molecular "ink".


Characterization Of Amino Acid Adlayers On Inas Surfaces Using X-Ray Photoelectron Spectroscopy, John Slavin, Upasana Jarori, Dmitry Zemlyanov, Albena Ivanisevic Mar 2012

Characterization Of Amino Acid Adlayers On Inas Surfaces Using X-Ray Photoelectron Spectroscopy, John Slavin, Upasana Jarori, Dmitry Zemlyanov, Albena Ivanisevic

Dmitry Yurievich Zemlyanov

Removal of surface oxide layers and the prevention of their reformation is an essential step in the use of Ill-V semiconductor technologies. Highlighted here are data exploring the use of amino acid (AA) self-assembled monolayers (SAMs) to block the pre-growth of oxides on indium arsenide surfaces. Three different AAs were used: lysine, aspartic acid, and cysteine. The adlayers were characterized by atomic force microscopy (AFM), Raman, and angle resolved X-ray photoelectron spectroscopy (ARXPS). AFM data suggest that the AA functional groups affect the packing and orientation of the molecules on the surfaces, reinforced by contact angle data. Raman data provide ...


Quantitative Evaluation Of Covalently Bound Molecules On Gap (100) Surfaces, Rosangelly Flores-Perez, Dmitry Zemlyanov, Albena Ivanisevic Mar 2012

Quantitative Evaluation Of Covalently Bound Molecules On Gap (100) Surfaces, Rosangelly Flores-Perez, Dmitry Zemlyanov, Albena Ivanisevic

Dmitry Yurievich Zemlyanov

The study utilizes surface sensitive techniques in order to quantitatively characterize the nature of organization and bonding of alkanethiol adsorbates on GaP (100) surfaces. The evaluation was performed using water contact angle, atomic force microscopy (AFM), Fourier transform infrared (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The hydrophobicity and consistency of surface roughness were studied via water contact angle and AFM. The FT-IR experimental protocol permitted the identification of characteristic functional groups on the surface and enabled insight into the organization within the adlayers on the GaP surface. XPS data showed evidence for the formation of a covalent bond between ...