title: Optical absorption enhancement in silicon nanowire arrays with a large lattice constant for photovoltaic applications.
abstract: In this paper, we use the transfer matrix method to calculate the optical absorptance of vertically-aligned silicon nanowire (SiNW) arrays. For fixed filling ratio, significant optical absorption enhancement occurs when the lattice constant is increased from 100 nm to 600 nm. The enhancement arises from an increase in field concentration within the nanowire as well as excitation of guided resonance modes. We quantify the absorption enhancement in terms of ultimate efficiency. Results show that an optimized SiNW array with lattice constant of 600 nm and wire diameter of 540 nm has a 72.4% higher ultimate efficiency than a Si thin film of equal thickness. The enhancement effect can be maintained over a large range of incidence angles.
authors.affiliation: Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA 90089, USA. chenxil@usc.edu
authors.forename: Chenxi
authors.initials: C
authors.lastname: Lin
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Povinelli
mesh_terms: D011211:Electric Power Supplies; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008027:Light; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D012031:Refractometry / Q000295:instrumentation*; D012542:Scattering, Radiation; D012825:Silicon / Q000737:chemistry*; D012993:Solar Energy
chemical_list: D012825:Silicon