Iranian Journal of Materials Science and Engineering

Silicon nanowires (SiNWs) are synthesized through a metal-assisted chemical etching (MACE) method using Si(100) substrates and silver (Ag) as a catalyst. Scanning electron microscope (SEM) images confirmed that length of prepared SiNWs was increased when etching time increased. The prepared SiNWs demonstrated considerably low light reflectance at a wavelength range of 200–1100 nm. The photoluminescence (PL) spectra of the grown SiNWs showed a broad emission band peaked at a wavelength of about 750 nm. A solar cell and photodetector based on heterojunction SiNWs/PEDOT:PSS were fabricated using SiNWs that prepared with different etching time and its J–V, sensitivity, and time response were investigated. The conversion efficiency of fabricated solar cell was increased from 0.39% to 0.68% when wire length decreased from 24 µm to 21 µm, respectively. However, the sensitivity of the heterojunction SiNWs/PEDOT:PSS photodetector was decreased from 53774% to 36826% when wire length decreased from 24 µm to 21 µm, respectively.

         The objectives of this work is to synthesize TiO₂/MgO nanocomposites using a pulse laser deposition technique. At a vacuum pressure of 2.5 10^-2 mBar, TiO₂/MgO nanocomposites were synthesized on substrates with a laser power of 600 mJ and a wavelength of 1064 nm. This search utilizes various pulses (500, 600, and 700) at a 6-Hertz repetition rate. X-ray diffraction was utilized to investigate crystallography of the phases in the samples, as well as average crystallite size (XRD). An increase in the average crystal size was observed with an increase in the number of shots (from 35.15 to 38.08) nm at (500 to 700) shots respectively. The impact of the number of laser shots on the surface characteristics of TiO₂/MgO nanocomposites was also evaluated using atomic force microscopy (AFM) and field emission scanning electron microscopy (FE-SEM). Finally, optical characteristics were evaluated using UV-Vis spectroscopy. Increasing the number of shots increased the absorbance and thus reduced the energy gap.