Self‐Assembled In‐Plane Growth of Mg₂SiO₄ Nanowires on Si Substrates Catalyzed by Au Nanoparticles

Abstract

In‐plane growth of Mg2SiO4 nanowires on Si substrates is achieved by using a vapor transport method with Au nanoparticles as catalyst. The self‐assembly of the as‐grown nanowires shows dependence on the substrate orientation, i.e., they are along one, two, and three particular directions on Si (110), (100), and (111) substrates, respectively. Detailed electron microscopy studies suggest that the Si substrates participate in the formation of Mg2SiO4, and the epitaxial growth of the nanowires is confined along the Si <110> directions. This synthesis route is quite reliable, and the dimensions of the Mg2SiO4 nanowires can be well controlled by the experiment parameters. Furthermore, using these nanowires, a lithography‐free method is demonstrated to fabricate nanowalls on Si substrates by controlled chemical etching. The Au nanoparticle catalyzed in‐plane epitaxial growth of the Mg2SiO4 nanowires hinges on the intimate interactions between substrates, nanoparticles, and nanowires, and our study may help to advance the developments of novel nanomaterials and functional nanodevices.

Synthesis of Mg₂Si/MgO Nanofibers Using SiO₂ Nanofibers in Mg Vapor

“…It has been reported that Mg 2 SiO 4 grains can be produced by the coalescence of MgO and SiO 2 grains [16]. In addition, Mg 2 SiO 4 and MgSiO 3 also would be formed using Mg and Si substrate under the appropriate partial pressure of oxygen [15]. However, in this experiment, their absence in the final products indicated by the XRD and TEM results.…”

“…• C) [15,18]. In other words, the reaction conditions of this experiment could not meet the requirement of the Mg 2 SiO 4 and Mg 2 SiO 3 formation.…”

“…[15]. In contrary to many other refractory metal-silicon-oxygen systems, Mg can form stable phases with Si and O, such as Mg 2 SiO 4 and MgSiO 3 .…”

Synthesis of Mg2Si nanorod arrays by the heat treatment of Si nanorod arrays under Mg vapor

“…Therefore, it is considered that the formation of Mg 2 Si should be preferred, which agrees with the results of this experiment. Additionally, the formation of Mg 2 SiO 4 and Mg 2 SiO 3 should be carried out at high temperatures (>800 o C) [14,16]. Thus, higher vacuum condition is expected to reduce the amount of O.…”

Surface‐Directed Nanoepitaxy on a Surface with an Irregular Lattice

“…[2,6] Surface-directed vaporliquid-solid (SVLS) growth of nanocrystals [7] has become known for its desirable characteristics, namely, precise and predictable positioning/orientation and elimination of post-growth nanowire (NW) alignment. [8][9][10] This approach exploits the surface crystal information of the substrate to laterally guide nanocrystals in predictable directions and has been demonstrated on a variety of materials including ZnO, [7] GaAs, [10] In 2 O 3 , [11,12] GaN, [13] Ge, [11] Mg 2 SiO 4 , [14] TiO 2 , [8] and ZnSe. [15] The compatibility of the SVLS growth process with semiconductors and conventional optical photolithography is expected to lead to breakthroughs in transitioning nanosystems to complex 2D and 3D architectures and ultimately to practical applications.…”