Controlled doping of GaAs nanowires is crucial for the development of nanowire-based electronic and optoelectronic devices. Here, we present a noncontact method based on time-resolved terahertz photoconductivity for assessing n- and p-type doping efficiency in nanowires. Using this technique, we measure extrinsic electron and hole concentrations in excess of 10(18) cm(-3) for GaAs nanowires with n-type and p-type doped shells. Furthermore, we show that controlled doping can significantly increase the photoconductivity lifetime of GaAs nanowires by over an order of magnitude: from 0.13 ns in undoped nanowires to 3.8 and 2.5 ns in n-doped and p-doped nanowires, respectively. Thus, controlled doping can be used to reduce the effects of parasitic surface recombination in optoelectronic nanowire devices, which is promising for nanowire devices, such as solar cells and nanowire lasers.
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http://dx.doi.org/10.1021/acsnano.5b07579 | DOI Listing |
Nanotechnology
January 2025
Laboratory of micro- and nanoelectronics, Saint Petersburg Electrotechnical University 'LETI', Prof. Popova st. 5, 197022 St.Petersburg, Russia.
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 n-type 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 NWs. 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 GaAs/Ni NWs, were obtained.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
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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