Photoresponse in epitaxial graphene with asymmetric metal contacts

2012 ◽  
Vol 100 (9) ◽  
pp. 093116 ◽  
Author(s):  
Ram Sevak Singh ◽  
Venkatram Nalla ◽  
Wei Chen ◽  
Wei Ji ◽  
Andrew T. S. Wee
2020 ◽  
Vol 10 (4) ◽  
pp. 1405 ◽  
Author(s):  
Ivan Shtepliuk ◽  
Mikhail Vagin ◽  
Rositsa Yakimova

Understanding the mechanism of metal electrodeposition on graphene as the simplest building block of all graphitic materials is important for electrocatalysis and the creation of metal contacts in electronics. The present work investigates copper electrodeposition onto epitaxial graphene on 4H-SiC by experimental and computational techniques. The two subsequent single-electron transfer steps were coherently quantified by electrochemistry and density functional theory (DFT). The kinetic measurements revealed the instantaneous nucleation mechanism of copper (Cu) electrodeposition, controlled by the convergent diffusion of reactant to the limited number of nucleation sites. Cu can freely migrate across the electrode surface. These findings provide fundamental insights into the nature of copper reduction and nucleation mechanisms and can be used as a starting point for performing more sophisticated investigations and developing real applications.


2011 ◽  
Vol 99 (7) ◽  
pp. 073506 ◽  
Author(s):  
V. K. Nagareddy ◽  
I. P. Nikitina ◽  
D. K. Gaskill ◽  
J. L. Tedesco ◽  
R. L. Myers-Ward ◽  
...  

Author(s):  
L.J. Chen ◽  
Y.F. Hsieh

One measure of the maturity of a device technology is the ease and reliability of applying contact metallurgy. Compared to metal contact of silicon, the status of GaAs metallization is still at its primitive stage. With the advent of GaAs MESFET and integrated circuits, very stringent requirements were placed on their metal contacts. During the past few years, extensive researches have been conducted in the area of Au-Ge-Ni in order to lower contact resistances and improve uniformity. In this paper, we report the results of TEM study of interfacial reactions between Ni and GaAs as part of the attempt to understand the role of nickel in Au-Ge-Ni contact of GaAs.N-type, Si-doped, (001) oriented GaAs wafers, 15 mil in thickness, were grown by gradient-freeze method. Nickel thin films, 300Å in thickness, were e-gun deposited on GaAs wafers. The samples were then annealed in dry N2 in a 3-zone diffusion furnace at temperatures 200°C - 600°C for 5-180 minutes. Thin foils for TEM examinations were prepared by chemical polishing from the GaA.s side. TEM investigations were performed with JE0L- 100B and JE0L-200CX electron microscopes.


Author(s):  
A.M. Letsoalo ◽  
M.E. Lee ◽  
E.O. de Neijs

Semiconductor devices require metal contacts for efficient collection of electrical charge. The physics of these metal/semiconductor contacts assumes perfect, abrupt and continuous interfaces between the layers. However, in practice these layers are neither continuous nor abrupt due to poor nucleation conditions and the formation of interfacial layers. The effects of layer thickness, deposition rate and substrate stoichiometry have been previously reported. In this work we will compare the effects of a single deposition technique and multiple depositions on the morphology of indium layers grown on (100) CdTe substrates. The electrical characteristics and specific resistivities of the indium contacts were measured, and their relationships with indium layer morphologies were established.Semi-insulating (100) CdTe samples were cut from Bridgman grown single crystal ingots. The surface of the as-cut slices were mechanically polished using 5μm, 3μm, 1μm and 0,25μm diamond abrasive respectively. This was followed by two minutes immersion in a 5% bromine-methanol solution.


Solar RRL ◽  
2021 ◽  
Author(s):  
Thibaud Hatt ◽  
Özde Ş. Kabakli ◽  
Patricia S. C. Schulze ◽  
Armin Richter ◽  
Stefan W. Glunz ◽  
...  

2021 ◽  
Vol 230 ◽  
pp. 111217
Author(s):  
Pradeep Padhamnath ◽  
Ankit Khanna ◽  
Naomi Nandakumar ◽  
Armin G. Aberle ◽  
Shubham Duttagupta

Nanophotonics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1391-1400
Author(s):  
Florian Laible ◽  
Kai Braun ◽  
Otto Hauler ◽  
Martin Eberle ◽  
Dieter P. Kern ◽  
...  

AbstractMechanically controllable break junctions are one suitable approach to generate atomic point contacts and ultrasmall and controllable gaps between two metal contacts. For constant bias voltages, the tunneling current can be used as a ruler to evaluate the distance between the contacts in the sub-1-nm regime and with sub-Å precision. This ruler can be used to measure the distance between two plasmonic nanostructures located at the designated breaking point of the break junction. In this work, an experimental setup together with suitable nanofabricated break junctions is developed that enables us to perform simultaneous gap-dependent optical and electrical characterization of coupled plasmonic particles, more specifically bowtie antennas in the highly interesting gap range from few nanometers down to zero gap width. The plasmonic break junction experiment is performed in the focus of a confocal microscope. Confocal scanning images and current measurements are simultaneously recorded and exhibit an increased current when the laser is focused in the proximity of the junction. This setup offers a flexible platform for further correlated optoelectronic investigations of coupled antennas or junctions bridged by nanomaterials.


2020 ◽  
Vol 1695 ◽  
pp. 012018
Author(s):  
I A Eliseyev ◽  
A V Babichev ◽  
S P Lebedev ◽  
P A Dementev ◽  
A V Zubov ◽  
...  
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