(poster) Bosch-etched nanojungle black silicon and its applications

Black silicon (b-Si) is a class of silicon materials featuring nanostructures that enable remarkable light absorption within the visible spectrum, earning it the designation “black” silicon. Its distinctively rough and nanostructured surface makes it suitable for various applications such as water-repellent surfaces and optoelectronics. Superhydrophobic surfaces derived from b-Si hold potential applications in industries like aviation and electronic packaging. Additionally, its
light-diffusing characteristics broaden its utility to fields like IoT and solar energy harvesting, enhancing absorption within the visible spectrum.

Traditional b-Si, represented as nanograss b-Si, is typically produced through cryo deep-etching, imposing a depth constraint of up to 4-5 μm. However, our recent innovation in fabrication, employing Bosch etching, has led to the emergence of a new iteration of b-Si known as nanojungle b-Si, with depths surpassing 10 μm. This development broadens the scope of potential applications for b-Si, encompassing the creation of resilient superhydrophobic surfaces and the diffusion of near-infrared light.

The durability of nanojungle b-Si was confirmed via a sand blasting abrasion assessment. In this experimental arrangement, a certain amount of sand were directed to impact samples positioned at a 45-degree angle from various
heights. We demonstrated that nanojungle b-Si maintained its superhydrophobic characteristic at heights reaching up to 40 cm, while nanograss b-Si ceased to exhibit this property beyond 20 cm.

The distinctive architecture of nanojungle b-Si grants it remarkable proficiency in diffusing near-infrared (NIR) light. Nearly 100% of the transmittance within the NIR spectrum is diffused. Consequently, haze values were calculated and compared with those of nanograss b-Si. In the case of nanograss b-Si, the haze was noted to be marginally below 60%.