Optical Modeling of Black Silicon for Solar Cells Using Effective Index Techniques

Abstract

Texturing the surface with both micro and nano scale features to form black silicon is a promising approach in improving solar cell efficiency. In optical modeling of such a surface, it is difficult to balance the accuracy and computational resource. In this work, we develop on a semianalytical model, effective index technique (EIT), which utilizes a finite-difference time domain (FDTD) method to represent the nanoscale texturing as an effective medium, and then apply this to microscale structures, which can then be modeled using the transfer matrix method and ray-tracing. We fabricate and model both periodic and random nanoscale textures, and analyze the accuracy of several effective index models against measured reflectivity. The limitations in the model are identified and coherency of the films is studied. The semianalytical method is shown to perform better than the other effective medium approaches for modeling black silicon and is applicable to modeling multiscale textures, whereas full numerical methods such as FDTD are not. However, although the EIT approach predicts the trends in antireflective performance of a texture, it remains inaccurate when compared with the experiment. Also, as with all effective medium approaches, the EIT does not account for light trapping through scattering.

Research on the Metasurface for Single-Photon Avalanche Photodiode

“…This is because when the size of the nanostructure is smaller than the wavelength of the incident light, the optical coupling can be enhanced by the refractive index grading effect. Nanostructures are usually fabricated by wet chemical etching, dry etching, or a combination of photoetching and dry etching [22][23][24][25]. By combining the mixed micro/nano textures on the Silicon surface, the broadband reflection can be suppressed to less than 10%, even without the use of any additional anti-reflection coating on the mixed textures [26][27][28].…”

Efficient light harvesting in hybrid quantum dot–interdigitated back contact solar cells via resonant energy transfer and luminescent downshifting

“…By having a top surface free of any contacts or doped regions, IBC solar cells are also ideal for investigating photon management structures. Photon management strategies based on nanostructures such as nanowire arrays, [17][18][19] nanoholes, 20 and pyramid arrays have previously been proposed. Using QDs on their own or combining them with photon management structures and textured surfaces could pave the way for new efficient hybrid photovoltaic technologies.…”

Anti-Reflectance Optimization of Secondary Nanostructured Black Silicon Grown on Micro-Structured Arrays

“…The metal-assisted wet etching method typically uses Ag or Au for nanoparticle catalysis and HF for etching substances [ 8 , 9 , 10 , 11 , 12 ], paying little attention to secondary nanostructures like plasma dry etching. Apart from the early references, recent papers have also rarely investigated secondary nanostructures [ 13 , 14 , 15 , 16 , 17 ]. Jia et al considered that a better surface structure would increase the performance of black silicon and thus they smoothed the surface with NaOH after wet etching [ 18 ].…”