# Recent Advances in Black Silicon Surface Modification for Enhanced Light Trapping in Photodetectors
## 5 Conclusions  
In conclusion, this work offers an extensive evaluation of recent advancements in the physical and chemical processing of BSi, emphasizing the potential of BSi structures for effectively trapping light in high-performance photodetectors. The recent work on BSi processing methods, including metal-assisted chemical etching, electrochemical etching, reactive ion etching, plasma etching, and laser ablation are reviewed with a keen interest in the resulting BSi micro- and nanostructures. Particularly, Ag-assisted MACE has demonstrated substantial performance improvements in broadband light absorption and reflectivity reduction, as observed in studies showing that this method substantially enhanced the efficiency of multi-crystalline BSi solar cells from 0.64% to 19.24% [24]. This review not only builds upon the foundal work of previous scholars but also presents our own contributions in the field of BSi fabrication. It delves deeply into the critical aspects of micro- and nanofabrication of BSi, offering an in-depth exploration of how a wide variety of processing techniques impact BSi. In addition, RIE and DRIE methods have shown the ability to create high-aspect-ratio nanostructures that reduce reflectance to as low as 1% and significantly enhance quantum efficiency, achieving up to 99% in some design cases [51]. On the other hand, laser ablation, particularly Se-doped BSi structures, has demonstrated remarkable broadband absorption (400-2200 nm), making it a viable method for advanced photodetectors with improved broadband responsivity [23]. This thorough investigation sets the stage for future developments in surface modification strategies for Si-based optical devices, particularly microstructures. Ultimately, the recent findings and implementations of BSi-based photodetectors are discussed. By optimizing BSi processing for light trapping, the potential of this material's properties in light trapping could pave the way for next-generation photodetectors with enhanced sensitivity and responsivity. Finally, while the methods reviewed in this manuscript such as metal-assisted chemical etching  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Method** & \begin{tabular}{c} **Light Absorption** \\ **Efficiency** \\ \end{tabular}  & **Fabrication Cost** & **Complexity** & **Scalability** & **Reference** \\ \hline Metal-Assisted & \begin{tabular}{c} High (can achieve \\ \textgreater{}90\% light absorption) \\ \end{tabular}  & \begin{tabular}{c} Low (uses \\ common chemicals \\ like Ag, Cu) \\ \end{tabular}  & \begin{tabular}{c} Moderate \\ (dependent on \\ control over \\ nanoparticle \\ formation) \\ \end{tabular}  & \begin{tabular}{c} High (scalable for large \\ surfaces, suitable for \\ industrial use) \\ \end{tabular}  & \begin{tabular}{c} [24; 25; 26; 27] \\ [24; 25; 27] \\ [24; 25; 26; 27] \\ [28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 50; 51; 52; 53] \\ Reactive Ion & \begin{tabular}{c} Very High (<1\% \\ reflectance over a \\ broad range) \\ \end{tabular}  & \begin{tabular}{c} Low (uses \\ common chemicals \\ like Ag, Cu) \\ \end{tabular}  & \begin{tabular}{c} Low (inexpensive \\ RIP or DRIE) \\ \end{tabular}  & \begin{tabular}{c} Low (simpler than \\ depends on etching \\ uniformity) \\ \end{tabular}  & \ \begin{tabular}{c} Medium (limited \\ scalability \\ depends on etching \\ uniformity) \\ \end{tabular}  &
\begin{tabular}{c} [40; 41] \\ [40; 41] \\ [42; 54] \\ [55] \\ [56; 57; 58; 59; 60; 61; 62; 63; 64; 65; 66; 67; 68; 69; 70; 71; 72; 73; 74; 75; 76; 77; 78; 79; 80; 81; 82; 83; 84; 85; 86; 87; 88; 89; 90; 91; 92; 9  
(MACE), reactive ion etching (RIE), and laser ablation have been primarily applied to rigid photodetectors, their adaptation for flexible photodetectors holds potential.