Nanostructured Silicon Matrix for Materials Engineering

Abstract

Tin‐containing layers with different degrees of oxidation are uniformly distributed along the length of silicon nanowires formed by a top‐down method by applying metalorganic chemical vapor deposition. The electronic and atomic structure of the obtained layers is investigated by applying nondestructive surface‐sensitive X‐ray absorption near edge spectroscopy using synchrotron radiation. The results demonstrated, for the first time, a distribution effect of the tin‐containing phases in the nanostructured silicon matrix compared to the results obtained for planar structures at the same deposition temperatures. The amount and distribution of tin‐containing phases can be effectively varied and controlled by adjusting the geometric parameters (pore diameter and length) of the initial matrix of nanostructured silicon. Due to the occurrence of intense interactions between precursor molecules and decomposition by‐products in the nanocapillary, as a consequence of random thermal motion of molecules in the nanocapillary, which leads to additional kinetic energy and formation of reducing agents, resulting in effective reduction of tin‐based compounds to a metallic tin state for molecules with the highest penetration depth in the nanostructured silicon matrix. This effect will enable clear control of the phase distributions of functional materials in 3D matrices for a wide range of applications.

Tin/Tin Oxide Nanostructures: Formation, Application, and Atomic and Electronic Structure Peculiarities

“…Many studies have described the CVD process of Sn-based thin films using SnCl 4 and SnI 4 as the tin precursors. In our previous studies, we also presented the deposition of Sn/SnO 2 thin films using tin(IV) tertbutoxide as the tin and oxygen source [42,43]. This method is fast and simple for depositing Sn/SnO 2 thin films with a dense structure, and the morphology and composition can be easily changed by varying the deposition temperatures and substrates, as we showed previously [38].…”

“…Chemical vapor deposition (CVD) has been widely used in the commercial deposi tion industry because of its inexpensive nature and flexibility in the production of synthe sis thin films and 1D nanostructures with high quality [38][39][40][41]. Many studies have de scribed the CVD process of Sn-based thin films using SnCl4 and SnI4 as the tin precursors In our previous studies, we also presented the deposition of Sn/SnO2 thin films using tin(IV) tert-butoxide as the tin and oxygen source [42,43]. This method is fast and simple (3) co-reactant process; (4) purge process [36].…”

Spectromicroscopy Studies of Silicon Nanowires Array Covered by Tin Oxide Layers

“…A detailed explanation of the new tin phase separation effect in silicon nanochannels is discussed in our latest publication. [ 32 ] A significant extension to the standard characterization results achieved via SEM and XRD for the SnO 2 –SiNWs composite array provides the precise information on the surface atomic and electronic structures. The role of the surface is evident because the SEM image (Figure 1a) showed that the surface of SiNWs is covered by a flat layer containing tiny grains, presumably of tin oxides and possibly with metallic tin, as suggested from XRD (Figure 1b).…”

“…Tin oxide thin films were deposited using a horizontal cold-wall reactor. [32,39] The substrates were heated by the inductive coupling of radiofrequency. Tin(IV) tert-butoxide (Sn(O t Bu) 4 ) [32,40] was used as a tin (Sn) and oxygen source.…”

“…[32,39] The substrates were heated by the inductive coupling of radiofrequency. Tin(IV) tert-butoxide (Sn(O t Bu) 4 ) [32,40] was used as a tin (Sn) and oxygen source. It was introduced into the reactor through a glass flange by applying a dynamic vacuum (10 −5 mbar) and heating the precursor to the ambient temperature (30-35 °C).…”