Doped catalyst-free GaAs nanowires have been grown by molecular beam epitaxy with the gallium-assisted method. The spatial dependence of the dopant concentration and resistivity have been measured by Raman spectroscopy and four point electrical measurements. Along with theoretical considerations, the doping mechanisms have been revealed. Two competing mechanisms have been revealed: dopant incorporation from the side facets and from the gallium droplet. In the latter incorporation path, doping compensation seems to play an important role in the effective dopant concentration. Hole concentrations of at least 2.4 x 10(18) cm(-3) have been achieved, which to our knowledge is the largest p doping range obtained up to date. This work opens the avenue for the use of doped GaAs nanowires in advanced applications and in mesoscopic physics experiments.
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http://dx.doi.org/10.1021/nl100157w | DOI Listing |
Nanotechnology
December 2024
Ioffe Institute, Politekhnicheskaya st. 29, Sankt-Peterburg, 194021, RUSSIAN FEDERATION.
The processes of electrochemical deposition of Ni on vertically aligned GaAs nanowires (NWs) grown by molecular-beam epitaxy (MBE) using Au as a growth catalyst on Si(111) substrates were studied. Based on the results of electrochemical deposition, it was concluded that during the MBE synthesis of NWs the self-induced formation of conductive channels can occur inside NWs, thereby forming quasi core-shell nanowires. Depending on the length of the channel compare to the NW heights and the parameters of electrochemical deposition, the different hybrid metal-semiconductor nanostructures, such as Ni nanoparticles on GaAs NW side walls, Ni clusters on top ends of GaAs NWs, core-shell Ni/GaAs NWs, were obtained.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Department of Physics, Universität Basel, Basel 4056, Switzerland.
A thermal diode, which, by analogy to its electrical counterpart, rectifies heat current, is the building block for thermal circuits. To realize a thermal diode, we demonstrate thermal rectification in a GaAs telescopic nanowire system using the thermal bridge method. We measured a preferred direction of heat flux, achieving rectification values ranging from 2 to 8% as a function of applied thermal bias.
View Article and Find Full Text PDFNanomaterials (Basel)
November 2024
Faculty of Physics, St. Petersburg State University, Universitetskaya Emb. 13B, 199034 St. Petersburg, Russia.
This study investigates the growth of gallium arsenide nanowires, using lead as a catalyst. Typically, nanowires are grown through the vapor-solid-liquid mechanism, where a key factor is the reduction in the nucleation barrier beneath the catalyst droplet. Arsenic exhibits limited solubility in conventional catalysts; however, this research explores an alternative scenario in which lead serves as a solvent for arsenic, while gallium and lead are immiscible liquids.
View Article and Find Full Text PDFNanotechnology
December 2024
School of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
ACS Appl Mater Interfaces
November 2024
NEST Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, 56127 Pisa, Italy.
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