Yaohui Zhan

Learn More
Single nanowire solar cells are a promising candidate as nanoelectronic power sources. Metallic cores were integrated in single nanowire solar cells, and the influence of the silver core on the absorption efficiency and the short circuit current was studied in this work. A Full-wave Vectorial Finite Element Method approach was used to rigorously solve(More)
Plasmonic Fano resonances arising from electromagnetic interactions in metallic nanostructures exhibit spectral characteristics analogous to those from the electron waves in oligomer molecules. Though a great deal of research interest has been attracted to study the optical properties and explore the associated applications of metallic nanoparticle(More)
Graphene's remarkable electrical and optical properties afford great potential for constructing various optoelectronic devices, including modulators, photodetectors and pulse lasers. In particular, graphene-based optical modulators were demonstrated to be featured with a broadband response, small footprint, ultrafast speed and CMOS-compatibility, which may(More)
An ultrathin amorphous silicon solar cell with conformal zig-zag nanoconfiguration is studied from both light-trapping and light-conversion perspectives. The design improves the front antireflection property, optimizes the rear metallic reflector, and elongates the optical path inside the photoactive layer. Compared to conventional nanoconfigurations, this(More)
Hot-electron photodetectors are attracting increasing interest due to their capability in below-bandgap photodetection without employing classic semiconductor junctions. Despite the high absorption in metallic nanostructures via plasmonic resonance, the fabrication of such devices is challenging and costly due to the use of high-dimensional sub-wavelength(More)
In this work, single-nanowire solar cells (SCs) in lying configuration with a tunable rear metallic film are presented. Compared to the standalone silicon nanowire (SiNW), a significant/broadband enhancement in the overall optical absorption of the SiNW with rear metallic nanoconfiguration was observed. The optimized fraction, corresponding to the maximal(More)
Tandem solar cells consisting of amorphous and microcrystalline silicon junctions with the top junction nanopatterned as a two-dimensional photonic crystal are studied. Broadband light trapping, detailed electron/hole transport, and photocurrent matching modulation are considered. It is found that the absorptances of both junctions can be significantly(More)
UNLABELLED A dual-diameter nanohole (DNH) photovoltaic system is proposed, where a top (bottom) layer with large (small) nanoholes is used to improve the absorption for the short-wavelength (long-wavelength) solar incidence, leading to a broadband light absorption enhancement. Through three-dimensional finite-element simulation, the core device parameters,(More)
We propose a design of crystalline silicon thin-film solar cells (c-Si TFSCs, 2 μm-thick) configured with partially embedded dielectric spheres on the light-injecting side. The intrinsic light trapping and photoconversion are simulated by the complete optoelectronic simulation. It shows that the embedding depth of the spheres provides an effective way to(More)
We propose an architecture of conformal metal-semiconductor-metal (MSM) device for hot-electron photodetection by asymmetrical alignment of the semiconductor barrier relative to the Fermi level of metals and strong energy localization through plasmonic resonances. Compared with the conventional grating design, the multi-layered grating system under(More)