title: A comparative study of absorption in vertically and laterally oriented InP core-shell nanowire photovoltaic devices.
abstract: We have compared the absorption in InP core-shell nanowire p-i-n junctions in lateral and vertical orientation. Arrays of vertical core-shell nanowires with 400 nm pitch and 280 nm diameter, as well as corresponding lateral single core-shell nanowires, were configured as photovoltaic devices. The photovoltaic characteristics of the samples, measured under 1 sun illumination, showed a higher absorption in lateral single nanowires compared to that in individual vertical nanowires, arranged in arrays with 400 nm pitch. Electromagnetic modeling of the structures confirmed the experimental observations and showed that the absorption in a vertical nanowire in an array depends strongly on the array pitch. The modeling demonstrated that, depending on the array pitch, absorption in a vertical nanowire can be lower or higher than that in a lateral nanowire with equal absorption predicted at a pitch of 510 nm for our nanowire geometry. The technology described in this Letter facilitates quantitative comparison of absorption in laterally and vertically oriented core-shell nanowire p-i-n junctions and can aid in the design, optimization, and performance evaluation of nanowire-based core-shell photovoltaic devices.
authors: Division of Solid State Physics and The Nanometer Structure Consortium (nmC@LU), Lund University , Box 118, 22100 Lund, Sweden.
authors: Ali
authors: A
authors: Nowzari
authors: Magnus
authors: M
authors: Heurlin
authors: Vishal
authors: V
authors: Jain
authors: Kristian
authors: K
authors: Storm
authors: Ali
authors: A
authors: Hosseinnia
authors: Nicklas
authors: N
authors: Anttu
authors: Magnus T
authors: MT
authors: Borgström
authors: Håkan
authors: H
authors: Pettersson
authors: Lars
authors: L
authors: Samuelson
keywords: InP; Nanowire; absorption; core−shell; photovoltaics; radial; solar cell