Hybrid metal-semiconductor cavities for multi-band perfect light absorbers and excellent electric conducting interfaces

It is desirable for optoelectronic devices to have the capability to simultaneously achieve excellent optical and electric features. Nevertheless, most investigations were performed separately for photon and electron management. In this work, we numerically propose and demonstrate a hybrid metal-semiconductor interface, which offers multi-band perfect light absorption and simultaneously retains the naturally perfect electrical conductivity of a flat metal film. Multi-band anti-reflection and near-unity light absorption is observed in this hybrid metal-semiconductor cavity based absorber (HMSA). Our results show that, the maximal absorption above 97% and the naturally perfect electric conductivity are realizable, suggesting the capability of providing both excellent optical and electric properties. Optical Mie-like resonances in the semiconductor cavities and the hybrid coupling with plasmonic resonances by the metal resonators cooperatively support strong optical field confinement effects, which eventually create the light trapped in the HMSA. These features indicate a platform wherein excellent electrical conducting and multispectral light absorption are designed for potential optoelectronic applications.