Abstract
We study the structure and optical properties of arrays of silicon nanowires (SiNWs) with a mean diameter of approximately 100 nm and length of about 1–25 μm formed on crystalline silicon (c-Si) substrates by using metal-assisted chemical etching in hydrofluoric acid solutions. In the middle infrared spectral region, the reflectance and transmittance of the formed SiNW arrays can be described in the framework of an effective medium with the effective refractive index of about 1.3 (porosity, approximately 75%), while a strong light scattering for wavelength of 0.3 ÷ 1 μm results in a decrease of the total reflectance of 1%-5%, which cannot be described in the effective medium approximation. The Raman scattering intensity under excitation at approximately 1 μm increases strongly in the sample with SiNWs in comparison with that in c-Si substrate. This effect is related to an increase of the light-matter interaction time due to the strong scattering of the excitation light in SiNW array. The prepared SiNWs are discussed as a kind of ‘black silicon’, which can be formed in a large scale and can be used for photonic applications as well as in molecular sensing.
Highlights
Silicon nanowires (SiNWs) are of great interest due to their potential applications in various fields suchlike microelectronics, optoelectronics, photonics, photovoltaics, biologic, and chemical sensors [1,2,3,4,5,6,7,8,9]
We study the morphology, microstructure, and optical properties of silicon nanowires (SiNWs) obtained by metal-assisted chemical etching (MACE) of crystalline silicon (c-Si) in hydrofluoric acid solution
The obtained experimental data on the structure and optical properties of silicon nanowire arrays prepared by metal-assisted chemical etching of c-Si in hydrofluoric acid solutions demonstrate new possibilities for tailoring the physical properties of Si-based nanostructures
Summary
Silicon nanowires (SiNWs) are of great interest due to their potential applications in various fields suchlike microelectronics, optoelectronics, photonics, photovoltaics, biologic, and chemical sensors [1,2,3,4,5,6,7,8,9]. SiNWs exhibit a strong optical absorption and rather low reflectance in the visible spectral range [4,6] as well as in room temperature photoluminescence (PL) [10,11]. It was demonstrated that SiNWs can be formed by top-down approaches suchlike a reactive ion etching, electrochemical etching, and metal-assisted chemical etching (MACE) [13,14,15,16,17,18,19]. Since both the electronic and optical properties of nanostructures. SiNWs exhibit efficient Raman scattering, and this effect can be interpreted in terms of the strong Anderson-like localization of the excitation light in the SiNW array
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
