Black silicon (b-Si) is an interesting bionic architecture for optoelectronics because of its extremely low reflectance on wide ranges of wavelength and incident angles. This Technology Offer is an original, efficient technique to produce wafer-scale (6-12 inches) subwavelength b-Si with an ultra-low light reflectance. As Germanium-X (X=metal) thin alloy film is acting as the self-mask layer, the fabrication process is also low cost and CMOS compatible.
The preliminary data shows a low reflectance of 1-3% (wavelength, 400-1000 nm) has been achieved by this black silicon technique, which results in a 30-50% efficiency enhancement of the photodetectors. The following are the features:
(1) CMOS-compatible, wafer-scale (6-12 inches), excellent repeatability and low costs;
(2) No mask/reticle is needed
(3) Morphology variable: nanowire, nanohole, nanopore and nanoneedle;
(4) The thin nanostructures are easy for conformal passivation.
The black silicon developed in this process exhibits enhanced optical absorption properties, making it promising for commercial applications in solar cells, photodetectors, and photocatalytic water splitting. The active surface area is essential for drug delivery, lithium-ion batteries, and various sensors.
Nowadays, the industries use many kinds of black silicon. Processes to nanotexture surfaces include metal-assisted wet etching, RIE, and laser processing. Black silicon providing broadband light antireflection has become a versatile substrate for photodetectors, photo-electrocatalysis, sensors, and photovoltaic devices. However, the existing fabrication methods mainly suffer from single morphology, chemical contaminations, low yield, or frangibility.
This original, efficient technique could produce wafer-scale (6-12 inches) subwavelength black silicon with an ultra-low light reflectance (1-3%, 400-1000 nm). It could enhance the efficiency of commercial silicon solar cells (>2%) and could reduce the manufacturing costs as well. Furthermore, this black silicon could used in the photodetector between the UV to IR wavelength with an enhanced photocurrent.