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Silicon nanowires (SiNWs) were synthesized by two-step electroless etching of p-type Si (100) wafer and characterized by field emission scanning electron microscopy, UV-Vis spectroscopy, x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and Raman spectroscopy. The vibrational signature at 1108 and 2087 cm−1 confirmed SiNWs were passivated by both oxygen and hydrogen atoms. Raman peak at 517 cm−1 indicated crystalline SiNWs with tailing toward redshift due to Fano effect. The Si(2p) and Si(2s) core orbital spectra of SiNWs were found at 99.8 and 150.5 eV, respectively. Moreover, the reflection of SiNWs is minimized to ~ 1 to 5% in the 650-nm wavelength. [ABSTRACT FROM AUTHOR]

Amorphous silicon carbide (a-SiC:H) thin films were synthesized using trichloromethylsilane by a hot wire chemical vapor deposition process. The deposited films were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, x-ray diffraction and x-ray photoelectron spectroscopy to confirm its chemical bonding, structural network and composition of the a-SiC:H films. The optical microscopy images reveal that hydrogen dilution increased the surface roughness and pore density of a-SiC:H thin film. The Raman spectroscopy and FTIR spectra reveal chemical network consisting of Si-Si, C-C and Si-C bonds, respectively. The XRD spectroscopy and Raman spectroscopy indicate a-SiC:H still has short-range order. In addition, in vitro cytotoxicity test ensures the behavior of cell-semiconductor hybrid to monitor the proper coordination. The live-dead assays and MTT assay reveal an increase in green nucleus cell, and cell viability is greater than 88%, respectively, showing non-toxic nature of prepared a-SiC:H film. Moreover, the result indicated by direct contact assay, and cell prefers to adhere and proliferate on a-SiC:H thin films having a positive effect as artificial heart valve coating material. [ABSTRACT FROM AUTHOR]

Highlights: [•] a-SiC:H, a-SiN:H, a-C:H and a-SiCN:H films were deposited by hot wire chemical vapor deposition. [•] Evolution of microstructure of a-SiCN:H films deposited at different NH3 flow rate were analyzed. [•] The chemical network of Si and C based alloys were studied by FTIR and Raman spectroscopy. [ABSTRACT FROM AUTHOR]

Abstract: We report the effect of H2 ambient annealing on the microstructure and vibrational properties of silicon nanowires (SiNWs) grown by atmospheric pressure chemical vapor depositions. The SiNWs were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Field-Emission Scanning Electron Microscopy (FESEM) and High-Resolution Transmission Electron Microscopy (HRTEM). The HRTEM study revealed that the thickness of oxide sheath surrounded by core silicon decreased with increasing H2 ambient annealing and consequently the vibrational spectra were changed. In FTIR spectra, the transverse optic and longitudinal optic peak positions of Si–O symmetry and asymmetry showed a blue shift of the outer oxide of SiNWs. The Si–O–Si peak position remained unchanged at 1080cm−1 while the integrated absorption of Si–O–Si vibration band decreased with increasing H2 flow rate. [Copyright &y& Elsevier]

Abstract: Hydrogenated amorphous silicon nitride (a-SiN:H) films were deposited by hot wire chemical vapour deposition (HWCVD) using SiH4 and NH3 as precursor gases. Fourier transmission infrared spectroscopy (FTIR), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) techniques were used to study the chemical and electronic environments of silicon and nitrogen atoms. The peak position of N (1s) shifts from 396.7eV to 401.7eV and FWHM increases from 1.32eV to 1.51eV as nitrogen content in a-SiN:H films increases from 39at.% to 75at.%. During the present investigation, it was observed that silicon network shifted to higher energy and, both the short-range order (SRO) and intermediate-range order (IRO) were found deteriorate due to incorporation of nitrogen in the silicon network. [Copyright &y& Elsevier]