Investigation of Structural and Infrared Characteristics of Silicon Nanowires for Bolometric Application

Nanostructures and microstructures are fabricated on silicon surfaces to reduce the reflection and enhance the absorption of light. It can be used to improve infrared (IR) absorption-based MEMS bolometer applications. The cost-effective metal-assisted chemical etching (MACE) method is used to synthesize the silicon nanowires arrays for surface roughness. The fabricated Si nanowires reveal roughly 5 times increment in the full-wave half-maxima (FWHM) of the X-ray rocking curve in comparison to crystalline silicon (c-Si) due to the presence of structural defects on the surface which arises because of the anisotropic chemical etching. Electron microscopy results confirm the formation of nanowires in Omni-directions with tens of nanometre diameter and a few μm lengths. The infrared response of silicon nanowires shows that the broadband infrared absorption is enhanced about 2.5 – 3 times compared to that of polished silicon for the IR range (2.5 – 20 μm). The IR response of the Si nanowires provides promising potential applications as broadband IR absorbing/ sensing material.