Princeton University

School of Engineering & Applied Science

Large-Area Nanofabrication and Applications in Advanced Nanoelectronic and Nanophotonic Devices

Wei Ding
B327 Engineering Quadrangle
Monday, October 19, 2015 - 3:00pm

The research work presents the novel large area nanofabrication techniques and their applications in advanced electronic and photonic devices with nanometer scale structures. The nanometer-scale, metallic structures are able to manipulate light in a way that bulk material or non-metallic nanostructures cannot. The research work includes simple and economical way to fabricate and highly improve the performances of 1) transparent electrodes, 2) organic solar cells and light emitting diodes, and 3) nonlinear optical devices. In the first part, a novel transparent electrode (TE), metallic deep subwavelength mesh electrode is developed and fabricated in large area (scalable to meter sizes), showing better transmittance, conductance and antiglare than previous TEs. In the second part, a nanostructured "sandwich" of metal and plastic is developed, named "plasmonic cavity with subwavelength hole-array (PlaCSH)", consisting of a thin mesh as a transparent front electrode, a thin metal back electrode, and in-between layer of active material. This structure can boost the performances of solar cells and LEDs. Experimentally, the PlaCSH solar cells achieve high light coupling-efficiency/absorptance/power conversion efficiency, along with broad-band, Omni angle/polarization acceptance. In LEDs, PlaCSH shows numerous benefits with both the small- molecule and polymer active materials. Enhanced light extraction, internal quantum efficiency, ambient light absorption, contrast, viewing angle, brightness, and decreased glare are all observed. The above experiments – along with simulations – confirm that PlaCSH can serve as an excellent optical antenna for both absorption and radiation. In the last part, a new plasmonic nonlinear light generation (NLG) structure, termed “Plasmonic-enhanced, Charge-Assisted Second-Harmonic generator” (p-CASH), is developed, and shows high second-harmonic generation (SHG) enhancement, large SHG tunability by bias, wide tuning range, and high stability. A new SHG tuning mechanism for p-CASH is proposed. The new structure, new properties and new understanding should open up new designs and applications of NLG.