Revealing the Loss Mechanism of Chemically-Induced Hot Electron Transport.

Hot electrons are crucial for unraveling the intrinsic relationship between chemical reactions and charge transfer in heterogeneous catalysis. Significant research focused on real-time detection of reaction-driven hot electron flow (chemicurrent) to elucidate the energy conversion mechanisms, but it remains elusive because carrier generation contributes to only part of the entire process. Here, a theoretical model for quantifying the chemicurrent yield is presented by clarifying the contributions of hot carrier losses from the internal emission and multiple reflections.

Enhancing the external quantum efficiency of Schottky barrier photodetectors through thin copper films.

Silicon-based Schottky barrier photodetectors (SBPDs) are a cost-effective alternative to compound semiconductor-based photodetectors by extending the silicon's photodetection range to the near-infrared (NIR) region. However, SBPDs still suffer from low quantum yield due to poor absorption in a metal layer and low emission efficiency of hot electrons. This study investigates the use of thin copper (Cu) films as a means of improving the performance of SBPDs operating in the NIR region.

Broadband single-channel coherent perfect absorption with a perfect magnetic mirror.

Two-channel coherent perfect absorption (CPA) enables absorption modulation as well as perfect absorption in a very simple way. However, because of its narrow and discrete operable wavelength range, the CPA has been limited to specific applications. In this work, we theoretically and experimentally demonstrate broadband single-channel CPA operable from the visible to near-infrared wavelengths, using an ultrathin absorbing material on a pseudo perfect magnetic mirror.

Optical analysis of the refractive index and birefringence of hexagonal boron nitride from the visible to near-infrared.

Two-dimensional materials such as hexagonal boron nitride (h-BN), graphene, and transition metal dichalcogenides have drawn great attention in various fields of photonics and electronics. Among them, h-BN has recently emerged as a promising material platform to study integrated quantum photonics due to its ultrabright quantum light emission capabilities. However, the fundamental optical properties of h-BN have not yet been investigated in the visible and near-infrared (NIR) spectrum thoroughly.

Ultrahigh omnidirectional, broadband, and polarization-independent optical absorption over the visible wavelengths by effective dispersion engineering.

Achieving perfect light absorption at a subwavelength-scale thickness has various advantageous in terms of cost, flexibility, weight, and performance for many different applications. However, obtaining perfect absorbers covering a wide range of wavelengths regardless of incident angle and input polarization without a complicated patterning process while maintaining a small thickness remains a challenge. In this paper, we demonstrate flat, lithography-free, ultrahigh omnidirectional, polarization-independent, broadband absorbers through effective dispersion engineering.

Ultra-compact silicon waveguide-integrated Schottky photodetectors using perfect absorption from tapered metal nanobrick arrays.

We propose and numerically analyze an integrated metal-semiconductor Schottky photodetector consisting of a tapered metal nanoblock chain on a silicon ridge waveguide. The metal-semiconductor junctions allow broadband sub-bandgap photodetection through the internal photoemission effects. The tapered array structures with different block widths can gradually tailor the cut-off frequencies and group velocities of the tightly confined plasmonic modes for enhanced light absorption and suppressed reflection of the photonic mode in the silicon waveguide.