title: High-efficiency nanostructured window GaAs solar cells.
abstract: Nanostructures have been widely used in solar cells due to their extraordinary optical properties. In most nanostructured cells, high short circuit current has been obtained due to enhanced light absorption. However, most of them suffer from lowered open circuit voltage and fill factor. One of the main challenges is formation of good junction and electrical contact. In particular, nanostructures in GaAs only have shown unsatisfactory performances (below 5% in energy conversion efficiency) which cannot match their ideal material properties and the record photovoltaic performances in industry. Here we demonstrate a completely new design for nanostructured solar cells that combines nanostructured window layer, metal mesa bar contact with small area, high quality planar junction. In this way, we not only keep the advanced optical properties of nanostructures such as broadband and wide angle antireflection, but also minimize its negative impact on electrical properties. High light absorption, efficient carrier collection, leakage elimination, and good lateral conductance can be simultaneously obtained. A nanostructured window cell using GaAs junction and AlGaAs nanocone window demonstrates 17% energy conversion efficiency and 0.982 V high open circuit voltage.
authors.affiliation: Department of Physics, ‡Department of Electrical Engineering, §Department of Materials Science and Engineering, and ∥Department of Applied Physics Stanford University , Stanford, California 94305, United States.
authors.forename: Dong
authors.initials: D
authors.lastname: Liang
authors.forename: Yangsen
authors.initials: Y
authors.lastname: Kang
authors.forename: Yijie
authors.initials: Y
authors.lastname: Huo
authors.forename: Yusi
authors.initials: Y
authors.lastname: Chen
authors.forename: Yi
authors.initials: Y
authors.lastname: Cui
authors.forename: James S
authors.initials: JS
authors.lastname: Harris
mesh_terms: D001152:Arsenicals / Q000737:chemistry*; D011211:Electric Power Supplies; D005708:Gallium / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry*; D055095:Optics and Photonics; D010316:Particle Size; D012993:Solar Energy; D013472:Sunlight
chemical_list: D001152:Arsenicals; C043055:gallium arsenide; D005708:Gallium