IEEE S.F. Bay Area Council e-GRID's
BayAreaTech

TUESDAY August 21, 2012
SCV Nanotechnology Chapter
Speaker: Dr. Jie Yao, Stanford University
Time: Registration & light lunch at 11:30 AM; Presentation at 12:00 Noon
Cost: IEEE Members and Students $5; Non-Members $10
Place: Texas Instruments Bldg E-1 CMA Room, 2900 Semiconductor Drive, Santa Clara
RSVP: from website
Web: www.ieee.org/nano

Light trapping across a wide band of frequencies is important for applications such as solar cells and photodetectors.? Here, we demonstrate a new approach to light management by forming whispering-gallery resonant modes inside a spherical nanoshell structure.? The geometry of the structure gives rise to a low quality-factor, facilitating the coupling of light into the resonant modes and substantial enhancement of the light path in the active material, thus dramatically improving absorption.? Using nanocrystalline silicon (nc-Si) as a model system, we observe broadband absorption enhancement across a large range of incident angles.? The absorption of a single layer of 50-nm-thick spherical nanoshells is equivalent to a 1-?m-thick planar nc-Si film.? This light-trapping structure could enable the manufacturing of high-throughput ultra-thin film absorbers in a variety of material systems that demand shorter deposition time, less material usage and transferability to flexible substrates.