Copper-Stabilized Si/Au Nanowhiskers for Advanced Nanoelectronic Applications

Abstract

We report here the growth and functional properties of silicon-based nanowhisker (NW) diodes produced by the vapor–liquid–solid process using a pulsed laser deposition technique. For the first time, we demonstrate that this method could be employed to control the size and shape of silicon NWs by using a two-component catalyst material (Au/Cu ≈ 60:1). During the NW growth, copper is distributed on the outer surface of the NW, whereas gold sticks as a droplet to its top. The length of NWs is defined by the total amount of copper in the catalyst alloy droplet. The measurements of the electrical transport properties revealed that in contact with the substrate, individual NWs demonstrate typical I – V diode characteristics. Our approach can become an important new tool in the design of novel electronic components.

Liquid-Assisted Vapor–Solid–Solid Silicon Nanowire Growth Mechanism Revealed by In Situ TEM When Using Cu–Sn Bimetallic Catalysts

“…(13)(14)(15)(16) The VSS mechanism with Cu 3 Si as catalyst has also been the object of a detailed analysis. (17) Metal alloys such as AuAg, (18) AuCu, (19) AuGa (20) and BiSn have been used as well and have proved to be efficient catalysts. (21) However, how SiNWs grow when the catalyst is made of a mixture of metals remains an open question.…”

“…The VLS mechanism with a Au-based eutectic as a catalyst, for the growth of ⟨111⟩-oriented semiconductor NWs, is particularly well documented, noticeably thanks to in situ transmission electron microscopy (TEM) observations. − The VSS mechanism with Cu 3 Si as a catalyst has also been the subject of a detailed analysis . Metal alloys such as AuAg, AuCu, AuGa, and BiSn have been used as well and have proved to be efficient catalysts . However, how SiNWs grow when the catalyst is made of a mixture of metals remains an open question.…”

Evolution of Cu-In Catalyst Nanoparticles under Hydrogen Plasma Treatment and Silicon Nanowire Growth Conditions

“…The electrical and optical properties of the NWs are strongly size- and structure-dependent [ 9 , 10 , 11 , 12 ], and catalyst NPs play a vital role in determining the NW size, structure, morphology, distribution, and orientation. In this respect, using compound catalysts gives an additional degree of freedom to monitor these parameters: for example, Ga-Au [ 13 ] and Cu-Au [ 14 ] catalysts have been proven advantageous in adjusting SiNW geometrical shape, size, and orientation; Bi-Sn [ 15 ] catalysts can lead to a doping effect in SiNWs; Al-Au [ 16 ] catalysts yield reliable epitaxial growth of SiNWs on single-crystalline silicon substrates; Ag-Au [ 17 ] catalysts are employed to form compositionally abrupt interfaces of Si/Ge/Si heterojunctions in NWs. In our previous works on the mechanisms of growth of SiNWs [ 18 , 19 ], we have illustrated how the use of a mixed catalyst—where one of the components is liquid and the other one is solid—increases even more these possibilities, in a mode we have called liquid-assisted-VSS (LAVSS).…”