Optical Confinement in Silicon Nanowire: A Correlated Characteristics and Fabrication of Vertically Aligned Nanowire

Here in this work, finite-difference time-domain (FDTD) analysis has been carried out to extract the optical characteristics of a single silicon nanowire (Si-NW) on a c-Si slab. Correlated absorption depth profile, electromagnetic field distribution, energy distribution and generation rate distributions of the Si-NW model showed the possibility of efficient light trapping within the nanowire. An experimental attempt has been taken to fabricate catalyst-induced vertically aligned Si-NWs. High-resolution field emission scanning electron microscope (FESEM) revealed the coverage of ca. 6.5×10⁸/cm² with a diameter in the range of 50-200 nm. Si-based nanostructures, particularly Si-NWs exhibit strong optical absorption with reference to those observed in conventional Si-based solar cells. Henceforth, Si-NW is a promising candidate in confining incident light and contributes in designing efficient and miniaturized solar cells.<br/> <br/>The sputtering technique was used to deposit a gold ultrathin film on the Si wafer and the film was annealed at a high temperature to achieve metal nanoparticles. Thereafter, a CVD reactor was used to grow Si-NWs. The morphology of as-fabricated Si-NWs was confirmed by SEM and high-resolution SEM investigations. Exciton generation rate distributions of vertically aligned Si-NWs of 50 and 200 nm diameters at 700 and 1100 nm solar spectral wavelengths have been simulated. Excitation rate distribution was found to be localized near the edges in both scenarios. At 700 nm wavelength confined spots were observed in a repeated fashion along with lower intensities, whereas at 1100 nm wavelength such spots increased in intensity and lower in repetition. Unlike those observed for Si-NW of 50 nm diameter, excitation rate distribution was found to be localized near the center with higher intensity at 700 nm solar wavelength, whereas at 1100 nm wavelength such distribution disappeared.<br/> <br/>During the fabrication process adopted here in this work, it was observed that metal nanoparticles acted as catalysts and were the main ingredient to define the diameter of the Si-NWs. FESEM observations confirmed the diameter of the as-grown Si-NWs to be in the range of 50 to 200 nm. In the simulation we have considered four different sizes of Si-NWs, such as 50, 100, 150 and 200 nm in diameters. Due to space constraints, further details are out of this context and will be elaborated in the event as well as in the full manuscript.<br/> <br/><i>Authors acknowledge Interdisciplinary Research Center for Renewable Energy and Power System (IRC-REPS), Research Institute, King Fahd University of Petroleum & Minerals (KFUPM), Dhahran 31261, Saudi Arabia (Grant # INRE2215).</i><br/>&lt;quillbot-extension-portal&gt;&lt;/quillbot-extension-portal&gt;