**6. Indium-catalyzed SiNWs grown by VLS mode**

### **6.1 Influence of indium oxide**

To study the indium oxide influence on the grown silicon nanowires, a comparative study is carried on. Silicon nanowires are grown using indium nanoparticles elaborated by the two different annealing processes: the conventional and the RTA annealing. **Figure 9(a)** and **(b)** shows the SEM images of the obtained nanowires. The elaborated indium particles have been treated by hydrogen gas with a flow rate of 60 sccm for 10 min before the silane introduction during 15 min.

As observed, the indium particles elaborated by conventional annealing morphology are enhanced and quasi-spherical particles are obtained. Despite this improvement, the SiNWs' density is very low due to the persistence of indium oxide after the hydrogen treatment as explained in Section 3. The indium oxide forming a shell around indium is decreasing its catalytic effect. To confirm the persistence of indium oxide, XRD of the obtained SiNWs is performed (**Figure 10**). In addition to silicon and indium peaks, we notice the presence of In2O3 peaks explaining the obtained low density.

Using indium particles elaborated at 450°C by the RTA process, the SiNWs' density is ameliorated, which is attributed to indium oxide's absence. The quasitotality of indium particles is active to catalyze the SiNWs' growth.

#### **Figure 9.**

*SEM images of (a) indium particles obtained by conventional annealing and the obtained SiNWs and (b) indium particles obtained by RTA annealing and the obtained SiNWs.*

**Figure 10.**

*XRD spectrum of SiNWs catalyzed by indium particles elaborated by conventional annealing.*

Indium particles catalyzing the growth are located on the top of the silicon nanowires confirming the VLS mode. Moreover, we notice that the SiNWs' morphology does not seem to depend on the annealing process. The obtained SiNWs in both cases are bent and kinked.

#### **6.2 Indium diffusion in SiNWs**

In order to study the indium diffusion in the obtained SiNWs, energy dispersive spectroscopy (EDS) is performed on the top and in the middle of a silicon nanowire. **Figure 11** shows that the wire is consisting of silicon only indicating that indium *Investigation of Indium Oxide Effect on Indium Particles Properties Used as Silicon Nanowires… DOI: http://dx.doi.org/10.5772/intechopen.93648*

does not diffuse in the contrary of other catalysts like gold. In addition to that, EDS performed on the catalyst particle shows that the particle is consisting of a indium-silicon alloy as explained by the VLS mode (**Table 1**).
