Enhanced broadband light absorption of ultrathin PtSe2 in metal–insulator–metal structure

Abstract

The enhancement of light absorption in an ultrathin two-dimensional material is critical for its optoelectronic and photonic applications. In this work, we investigated the enhanced light absorption of layered PtSe2 by engineering the optical impedance and the attenuation of the PtSe2-based metal–insulator–metal (MIM) absorber. For a monolayer PtSe2-based MIM absorber, the undesirable impedance mismatch can be compensated for using the top patterned metal array in the MIM structure to achieve near-perfect absorption (99.95%), and the absorption of monolayer PtSe2 is enhanced by 8.6 times in the visible spectra. For a few-layer PtSe2 MIM absorber, the self-impedance of the PtSe2 layer becomes an important factor in modulating the optical absorption and the PtSe2-based absorbers show excellent features with broadband absorption, insensitive to the incident angle and polarization. Our results improve the viability of the PtSe2-based optoelectronic and photonic devices and shed light on the design of absorbers with hybrid 2D materials.