A New Route to Large‐Scale Synthesis of Silicon Nanowires in Ultrahigh Vacuum

Abstract

An approach for the large‐scale synthesis of high‐purity silicon nanowires (SiNWs) in ultrahigh vacuum is presented. A mixture of Si and SiO2 is evaporated by an electron beam, and the growth temperature is 700 °C, which is much lower than those used for other oxide‐assisted growths. A new type of single‐crystal SiNWs, with [221] orientation, is thus synthesized. Moreover, it is experimentally demonstrated that SiO intermediates are formed in the process, and the nanowires are obtained via a disproportionation reaction of 2SiO → Si + SiO2. A growth mechanism is proposed and the critical factors for the formation of 1D nanowires are also determined. The approach is particularly compatible with the mature Si‐based technology, and is favorable for device integration and practical applications.

Stress Engineering of SiNx Films for Modifying Optical and Mechanical Properties

“…Finally, XPS Si 2p core lines with a shape of negative asymmetry, whose main signals are located at ∼101.1 eV and assigned to Si−N bonds, − appear and do not vary with the sputtering time once more. These reveal that highly oxidized compound (SiO 2 ) presents at the top surface, followed by a transition layer, and finally silicon nitride (SiN x ) distributed very uniformly at the bottom layer. The same conclusion could be drawn from the XPS N 1s spectra.…”

“…Figure a displays the XPS Si 2p spectra collected from the 110-nm SiN x /Si(100) as a function of Ar + sputtering time. It is seen that Si 2p signal first appears at the binding energy of ∼103.0 eV, corresponding to O−Si−O bonds, , and then rapidly shifts to lower binding energies after Ar + sputtering. Moreover, the shape of Si 2p peak is observed to first broaden asymmetrically toward high binding energies (positive asymmetry) and then toward low binding energies (negative asymmetry).…”

One-step chemical vapor deposition synthesis of Si NWs@C core/shell anodes without additional catalysts by the oxide-assisted growth mechanism for lithium-ion batteries

“…Furthermore, the SiO 2 layer formed around the Si NWs acts as a barrier, preventing further diameter expansion. [21][22][23] When the carbon atmosphere is introduced at a certain temperature, the pyrolysis of incoming CH 4 to produce C occurs, which then encapsulates the Si NWs by forming a carbon shell on the outside. The synthesis process for the Si NWs@C core/shell nanocomposites is characterized by its inherent simplicity, as it involves a single-step deposition method under temperature control.…”

Silicon nanowires prepared by electron beam evaporation in ultrahigh vacuum

“…This phenomenon (Figure 4 ) is completely different from that in VLS process (Figure 1 ). According to our previous study [ 16 ], SiNWs (Figure 4b ) are grown by OAG via a disproportionation reaction of 2SiO → Si + SiO 2 . The SiO intermediates are created by electron beam bombardment on the mixed Si and SiO 2 and play an important role in the SiNWs formation [ 16 ].…”

“…According to our previous study [ 16 ], SiNWs (Figure 4b ) are grown by OAG via a disproportionation reaction of 2SiO → Si + SiO 2 . The SiO intermediates are created by electron beam bombardment on the mixed Si and SiO 2 and play an important role in the SiNWs formation [ 16 ]. Firstly, SiO can be bonded to the SiO 2 surface through the overlap between the empty Si π 2p * orbits and the lone pair filled O 2p orbits (formation of an intermolecular Si ← O donor-acceptor bond) [ 26 ], which contributes the generation of stable nuclei for the growth of SiNWs.…”