ALD-passivated silicon nanowires for broadband absorption applications

Silicon photonics enables the fabrication of optical devices with standard semiconductor processing technology. With high transparency and modal confinement, Si has matured into a well-established infrared optical material. Nanostructured silicon has been studied extensively due to its optical properties, especially silicon nanowires due to the myriad of available fabrication techniques, the broad range of physical dimensions, and the resulting optical characteristics. In this study, we fabricate silicon nanowires using a wet chemical process and modify their absorptive properties via atomic layer deposition passivation. The passivated nanowires absorb 95% of light from the visible to infrared, with a minimal angular dependence, making them excellent candidates for broadband absorber applications.