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Search Publications by: Nikolai Zhitenev (Fed)

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Displaying 26 - 50 of 114

Interaction-driven quantum Hall wedding cake-like structures in graphene quantum dots

August 24, 2018
Author(s)
Christopher Gutierrez, Daniel T. Walkup, Fereshte Ghahari Kermani, Cyprian Lewandowski, Joaquin R. Nieva, Kenji Watanabe, Takashi Taniguchi, Leonid Levitov, Nikolai Zhitenev, Joseph A. Stroscio
Interactions amongst relativistic particles underpin exotic behaviours in diverse systems ranging from quark-gluon plasmas to Dirac electron fluids in solids. Despite long-standing interest, direct observation of quantum-relativistic matter under ambient

Improving dielectric nanoresonator array coatings for solar cells

June 19, 2018
Author(s)
Dongheon Ha, Nikolai B. Zhitenev
We introduce single layer silicon dioxide (SiO2) nanosphere arrays as antireflection coatings (ARCs) on a gallium arsenide (GaAs) solar cell. We make macro- and nanoscale experiments and finite-difference time-domain (FDTD) calculations to prove the

Nanoscale photocurrent mapping in perovskite solar cells

June 1, 2018
Author(s)
Yohan Yoon, Dongheon Ha, Ik Jae Park, Paul M. Haney, Sangwook Lee, Nikolai Zhitenev
In this work, we study spatially-resolved generation of photocurrent of methylammonium lead iodide (CH3NH3PbI3) perovskite solar cells to reveal the microscopic effects of annealing temperature and degradation under light exposure. Correlating a novel

Paper in electronic and optoelectronic devices

March 6, 2018
Author(s)
Dongheon Ha, Zhiqiang Fang, Nikolai B. Zhitenev
The demand for lightweight, cost-effective, and/or flexible electronic and optoelectronic devices drives research toward new materials advancing the desired functionality or reducing manufacturing costs. Paper, being in addition an earth abundant and

Stateful characterization of resistive switching TiO2 with electron beam induced currents

December 7, 2017
Author(s)
Brian D. Hoskins, Gina C. Adam, Evgheni Strelcov, Nikolai B. Zhitenev, Andrei A. Kolmakov, Dmitri B. Strukov, Jabez J. McClelland
Metal oxide resistive switches have become increasingly important as possible artificial synapses in next generation neuromorphic networks. Nevertheless, there is still no codified set of tools for studying fundamental properties of the devices. To this

Local measurements of photocurrent and band gap in CdTe solar cells

September 25, 2017
Author(s)
Yohan Yoon, Jungseok Chae, Aaron M. Katzenmeyer, Heayoung Yoon, Joshua D. Schumacher, Sang M. An, Andrea Centrone, Nikolai B. Zhitenev
Polycrystalline thin film technology has shown great promise for low cost, high efficiency photovoltaics. To further increase the power efficiency, a firm understanding of microstructural properties of the devices is required. In this work, we investigate

Strain engineering a 4a*?3a charge-density-wave phase in transition-metal dichalcogenide 1T-VSe2

July 19, 2017
Author(s)
Duming Zhang, Jeonghoon Ha, Hongwoo H. Baek, Yang-Hao Chan, Donat F. Natterer, Alline Myers, Joshua D. Schumacher, William Cullen, Albert Davydov, Young Kuk, Mei-Yin Chou, Nikolai Zhitenev, Joseph A. Stroscio
We report a new charge density wave (CDW) structure in strained 1T-VSe2 thin films synthesized by molecular beam epitaxy. The CDW structure is unconventional and exhibits a rectangular 4a×√3a periodicity, as opposed to the previously reported hexagonal 4a

An On/Off Berry Phase Switching with Circular Graphene Resonators

May 26, 2017
Author(s)
Fereshte Ghahari Kermani, Daniel T. Walkup, Christopher Gutierrez, Joaquin R. Nieva, Yue Y. Zhao, Jonathan E. Wyrick, Donat F. Natterer, William G. Cullen, Kenji Watanabe, Takashi Taniguchi, Leonid Levitov, Nikolai B. Zhitenev, Joseph A. Stroscio
Berry phase is an example of anholonomy, where the phase of a quantum state may not return to its original value after its parameters cycle around a closed path; instead the quantum system’s wavefunction may acquire a real measurable phase difference

Nanoscale Imaging and Spectroscopy of Band Gap and defects in Polycrystalline Photovoltaic Devices

April 12, 2017
Author(s)
Yohan Yoon, Jungseok Chae, Aaron M. Katzenmeyer, Heayoung Yoon, Joshua D. Schumacher, Sang M. An, Andrea Centrone, Nikolai B. Zhitenev
Improving the power conversion efficiency of photovoltaic (PV) devices is challenging because the generation, separation and collection of electron-hole pairs in PV devices is strongly dependent on details of the nanoscale chemical composition and defects

Depletion region surface effects in electron beam induced current measurements

September 7, 2016
Author(s)
Paul M. Haney, Heayoung Yoon, Benoit H. Gaury, Nikolai B. Zhitenev
Electron beam induced current (EBIC) is a powerful characterization technique which offers the high spatial resolution needed to study polycrystalline solar cells. Ideally, an EBIC measurement reflects the spatially resolved quantum efficiency of the

Scanning tunneling spectroscopy of proximity superconductivity in epitaxial multilayer graphene

January 7, 2016
Author(s)
Donat F. Natterer, Jeonghoon Ha, Hongwoo H. Baek, Duming Zhang, William G. Cullen, Nikolai B. Zhitenev, Young Kuk, Joseph A. Stroscio
Superconducting aluminum films were grown on multilayer graphene. The aluminum films were discontinuous with networks of trenches in the film morphology reaching down to the substrate to exposed graphene terraces. Superconductivity was induced in