Publications de Kannan Balasubramanian

Identifying Chemical Functionalization on Individual Carbon Nanotubes and Graphene by Local Vibrational Fingerprinting

Chemical functionalization of carbon nanotubes (CNTs) and graphene allows for fine-tuning their physical and chemical properties to realize fascinating new fundamental phenomena as well as exotic applications. A primary challenge in such endeavors is the n ...

Amer Chemical Soc2015

Real-Time Label-Free Direct Electronic Monitoring of Topoisomerase Enzyme Binding Kinetics on Graphene

Klaus Kern, Kannan Balasubramanian

Mono layer graphene field-effect sensors operating in liquid have been widely deployed for detecting a range of analyte species often under equilibrium conditions. Here we report on the real-time detection of the binding kinetics of the essential human enz ...

Amer Chemical Soc2015

Tuning the isoelectric point of graphene by electrochemical functionalization

Klaus Kern, Kannan Balasubramanian

The ability to control the charge-potential landscape at solid-liquid interfaces is pivotal to engineer novel devices for applications in sensing, catalysis and energy conversion. The isoelectric point (pI)/point of zero charge (pzc) of graphene plays a ke ...

Nature Publishing Group2015

Enhancing the Electrochemical and Electronic Performance of CVD-Grown Graphene by Minimizing Trace Metal Impurities

Klaus Kern, Kannan Balasubramanian

The presence of unwanted impurities in graphene is known to have a significant impact on its physical and chemical properties. Similar to carbon nanotubes, any trace metals present in graphene will affect the electrocatalytic properties of the material. He ...

Wiley-V C H Verlag Gmbh2014

Tunable Enhancement of Raman Scattering in Graphene-Nanoparticle Hybrids

Klaus Kern, Kannan Balasubramanian

The realization of graphene-gold-nanoparticle (G-AuNP) hybrids is presented here through a versatile electrochemical approach, which allows the continuous tuning of the size and density of the particles obtainable on the graphene surface. Raman scattering ...

Wiley-V C H Verlag Gmbh2014

25th Anniversary Article: Label-Free Electrical Biodetection Using Carbon Nanostructures

Klaus Kern, Kannan Balasubramanian

Nanostructures are promising candidates for use as active materials for the detection of chemical and biological species, mainly due to the high surface-to-volume ratio and the unique physical properties arising at the nanoscale. Among the various nanostru ...

Wiley-V C H Verlag Gmbh2014

Field-effect-based chemical sensing using nanowire-nanoparticle hybrids: The ion-sensitive metal-semiconductor field-effect transistor

Klaus Kern, Kannan Balasubramanian, Vivek Pachauri

A new class of nanoscale devices called ion-sensitive metal-semiconductor field-effect transistors (nano-IS-MESFET) for sensing applications is reported. Nanoparticle-nanowire hybrids with active metal-semiconductor regions are operated as ion-sensitive fi ...

Amer Inst Physics2013

Spatially resolved photocurrents in graphene nanoribbon devices

Klaus Kern, Kannan Balasubramanian, Stephan Rauschenbach, Marko Burghard, Adarsh Singh Sagar, Thomas Dufaux

We present here a scanning photocurrent microscopy study of individual graphene nanoribbons, revealing pronounced photocurrent responses close to the nanoribbon/metal contacts. The magnitude of the corresponding photocurrent signal was found to be directly ...

Amer Inst Physics2013

Chemically exfoliated large-area two-dimensional flakes of molybdenum disulfide for device applications

Klaus Kern, Kannan Balasubramanian, Vivek Pachauri

A solution-based exfoliation method for obtaining large-area two-dimensional flakes of molybdenum disulfide, followed by the fabrication of electrical devices is presented in this manuscript. The exfoliation method is based on the use of an aprotic solvent ...

Amer Inst Physics2013

Self-Assembled Electrical Biodetector Based on Reduced Graphene Oxide

Klaus Kern, Kannan Balasubramanian, Ravi Shankar Sundaram, Subramanian Sundaram

Large-scale fabrication of graphene-based devices is an aspect of great importance for various applications including chemical and biological sensing. Toward this goal, we present here a novel chemical route for the site-specific realization of devices bas ...

2012

Electric field effect in graphite crystallites

Klaus Kern, Kannan Balasubramanian, Marko Burghard, Adarsh Singh Sagar

Graphite is a highly anisotropic crystal with a quasi-two-dimensional electronic structure exhibiting high intrinsic charge carrier mobility. Here, we investigate the effect of an electric field on the resistance of individual graphite crystallites with a ...

AIP American Institute of Physics2012

Polymer-electrolyte gated graphene transistors for analog and digital phase detection

Klaus Kern, Kannan Balasubramanian, Marko Burghard, Adarsh Singh Sagar

We present an alternating current (ac) circuit based on a misoriented bilayer graphene device for analog and digital phase detection. We exploit the ambipolar nature of the transfer characteristics of a misoriented bilayer graphene transistor. The transist ...

AIP American Institute of Physics2011

Label-Free Detection of Few Copies of DNA with Carbon Nanotube Impedance Biosensors

Klaus Kern, Kannan Balasubramanian

Wiley-VCH Verlag GmbH2011

Template-free self-assembly of hierarchical ZnO structures from nanoscale building blocks

Klaus Kern, Kannan Balasubramanian, Vivek Pachauri

We study chemical bath deposition method for synthesizing large variety constructions of ZnO nanostructures. By varying reaction kinetics we control the shape, size and morphology to yield flower-like, rolling-pin-like, viscous-fingers-like and antenna-lik ...

Elsevier2010

Enzyme-Free Sugar Sensing in Microfluidic Channels with an Affinity-Based Single-Wall Carbon Nanotube Sensor

Klaus Kern, Kannan Balasubramanian

We present a novel nonenzymatic carbon nanotube sensor integrated in a microfluidic channel for the detection of sugars. The sensor is assembled as a liquid-gated field-effect transistor, with the transistor channel composed of 1 to 10 nanotubes, which are ...

2010

Marker-free on-the-fly fabrication of graphene devices based on fluorescence quenching

Klaus Kern, Kannan Balasubramanian, Adarsh Singh Sagar

Graphene has been dominating the electronic research community recently, with a brisk surge in proposals for its use in novel devices. The aspirations of 2D-carbon-based electronics largely rely on the availability of a mass-production technique to obtain ...

2010

Site-Specific Self-Assembled Liquid-Gated ZnO Nanowire Transistors for Sensing Applications

Klaus Kern, Kannan Balasubramanian, Vivek Pachauri

A scalable bottom-up solution-based approach for the site-specific realization of ZnO nanowire (ZnO-NW)-based field-effect transistors for sensing applications in liquids is reported. The nanowires are grown across pre-defined electrodes patterned by photo ...

2010

Spatially Resolved Potential Distribution in Carbon Nanotube Cross-Junction Devices

Klaus Kern, Kannan Balasubramanian, Marko Burghard, Eduardo Jian Hua Lee

Crossed-nanotube junctions, the basic constituents of carbon nanotube networks, are investigated by scanning photocurrent microscopy. The location of the predominant electrostatic potential drop, at the electrical contacts or at the junction, is found to b ...

Wiley2009

Selective Enhancement of Carbon Nanotube Photoluminescence by Resonant Energy Transfer

Klaus Kern, Kannan Balasubramanian

We report on a simple method for enhancing the efficiency of photoluminescence (PL) emission from selected chiral forms of semiconducting single-wall carbon nanotubes (SWCNTs). The method is based on the use of a fluorescent dye (Nile blue A) that shows th ...

2009

Effect of Stacking Order on the Electric-Field Induced Carrier Modulation in Graphene Bilayers

Klaus Kern, Kannan Balasubramanian, Marko Burghard, Eduardo Jian Hua Lee, Adarsh Singh Sagar

When planar graphene sheets are stacked on top of each other, the electronic structure of the system varies with the position of the subsequent sublattice atoms. Here, we employ scanning photocurrent microscopy to study the disparity in the behavior of cha ...

American Chemical Society (ACS)2009