Fully controllable silicon nanowire fabricated using optical lithography and orientation dependent oxidation

Silicon nanowires (SiNWs) exhibit unique electrical, thermal, and optical properties compared to bulk silicon which make them suitable for various device applications. To realize nanowires in real applications, large-scale and low-cost fabrication method is required. Here, we demonstrate a simple, low-cost fabrication process to produce silicon nanowires (SiNWs) with full controllability of size and length. The nanowires are fabricated using optical lithography and orientation dependent oxidation. Highly uniform single crystalline nanowires with thicknesses down to 10 nm, lengths up to 3 cm and aspect ratios up to approximately 300,000 are formed with high yield. The technology is further simplified to fabricate more complex structure such as metal-oxidesemiconductor field-effect-transistors (MOSFETs) by means of the selective etching of silicon without the need for extra steps. This method is distinct from other top-down techniques, where the formation of nanowires at low-cost, using simple processing steps, with high controllability and reproducibility is major challenge. This controllable and CMOS-compatible technology can offer a practical route to fabricate nanostructures with tuneable properties that can be the key for many device applications including nanoelectronics, thermoelectric and biosensing.