Large area and broadband gold-black absorber and the nanocone-like array model

Abstract

Broadband light absorbers are attractive for their applications in photodetection and thermal detectors. Metal-black coatings have been experimentally proven to have broadband light absorption characteristic. A large area and broadband gold-black coating was fabricated by a low-cost but effective sputtering process. The gold-black films exhibited reduced reflection of 4.81%, 2.48% and 1.93% for sputtering pressure of 50, 65 and 80 Pa in 300-800 nm spectral range, and their size reached 4- inches. A three-dimensional nanocone-like array model was proposed for the gold-black films. Then, the nanocone array of this model was embedded with many gold nanoparticles due to the rough surface of the gold-black films. The results indicated this proposed model of nanocone-like array embedded with nanoparticles can be a good tool to design broadband gold-black absorbers.