Enhanced broadband light absorption of ultrathin PtSe 2 in metal–insulator–metal structure

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 PtSe 2 by engineering the optical impedance and the attenuation of the PtSe 2 -based metal–insulator–metal (MIM) absorber. For a monolayer PtSe 2 -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 PtSe 2 is enhanced by 8.6 times in the visible spectra. For a few-layer PtSe 2 MIM absorber, the self-impedance of the PtSe 2 layer becomes an important factor in modulating the optical absorption and the PtSe 2 -based absorbers show excellent features with broadband absorption, insensitive to the incident angle and polarization. Our results improve the viability of the PtSe 2 -based optoelectronic and photonic devices and shed light on the design of absorbers with hybrid 2D materials.