Ultraviolet Interband Plasmonics With Si Nanostructures

Abstract

Although Si acts as an electrical semiconductor, it has properties of an optical dielectric.Here, we revisit the behavior of Si as a plasmonic metal. This behavior was previously shown to arise from strong interband transitions that lead to negative permittivity of Si across the ultra-violet spectral range. However, so far, few have studied the plasmonic characteristics of Si, particularly in its nanostructures. In this paper, we report localized plasmon resonances in Si nanostructures and the observation of plasmon hybridization in the UV (~250 nm wavelength). In addition, simulation results show that Si nanodisk dimers can achieve a local intensity enhancement greater than ~500-fold in a 1 nm gap. Lastly, we investigate hybrid Si-Al nanostructures to achieve sharp resonances in the UV, due to the coupling between plasmon resonances supported by Si and Al nanostructures. These results will have potential applications in the UV range, such as nanostructured devices for spectral filtering, plasmon enhanced Si photodetectors, interrogation of molecular chirality, and catalysis. It could have significant impact on UV photolithography on patterned Si structures.

All-dielectric metasurface for high-performance structural color

“…From the material side, silicon is extremely stable and compatible to the modern CMOS technologies, naturally matching the requirements on mass-manufacturability and long-time durability [18][19][20][32][33][34] . The sophisticated design on nanostructures gives the possibility of concealing its shortage and improving the color impression 20,[35][36][37] . In addition, the large refractive index of Si enables simple structures for highperformance structural color, essential for the cost-effective nanofabrication 20,38,39 .…”

Mesoscopic electrodynamics at metal surfaces

“…Nonlocal effects exist also in this situation, which have been explored in hydrodynamic models [69,70,337]. In passing, we note that even undoped semiconductors can host nonlocal phenomena associated with excitons [338], and also interband transitions can resemble plasmonic behavior [74].…”

“…In passing, we note that there is now also growing attention to plasmon-like behavior associated with negative dielectric function values. This can be due to electronic interband transitions, including the possible interband response in graphene [30,67,73] and in silicon [74], while the negative response may also be caused by phonon polaritons, such as in polar dielectrics [75].…”

Polarizable High‐Index Nanoparticles Used for Light‐Induced Crystal‐Silicon Passivation and Dielectric Antenna for High‐Efficiency Solar Cell

“…The dielectrics of the c-Si and ITO were from Palik, [37] and the dielectrics of the a-Si and the perovskite were from the literature. [29,38]…”