Nonmetallic Broadband Visible-Light Absorbers With Polarization and Incident Angle Insensitivity

We have proposed and theoretically analyzed nonmetallic broadband visiblelight absorbers based on alternating SiO2/InAs thin films on SiO2 substrate. Compared with the conventional absorbers, the proposed SiO2/InAs structure can achieve excellent absorption within a smaller volume. The average absorption can exceed 97% in the wavelength range of 300-850 nm. With a two-dimensional InAs grating atop, the device can achieve the average absorption of >92% with insensitivity to light polarization and incident angles. Due to the advantages of broadband and near-unity absorption, polarization and incident angle insensitivity, controllable and mature fabrication processes, the proposed visible-light absorbers will find wide applications in solar energy harvesting, thermal emission, and water splitting.