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Scalable, epitaxy-free fabrication of super-absorbing sparse III-V nanowire arrays for photovoltaic applications

Cheng, Wen-Hui and Fountaine, Katherine T. and Bukowsky, Colton R. and Atwater, Harry A. (2016) Scalable, epitaxy-free fabrication of super-absorbing sparse III-V nanowire arrays for photovoltaic applications. In: Next Generation Technologies for Solar Energy Conversion VII. Proceedings of SPIE. No.9937. Society of Photo-optical Instrumentation Engineers (SPIE) , Bellingham, WA, Art. No. 99370D . ISBN 9781510602656. http://resolver.caltech.edu/CaltechAUTHORS:20180706-091842084

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Abstract

III-V compound semiconductor nanowire arrays are promising candidates for photovoltaics applications due to their high volumetric absorption. Uniform nanowire arrays exhibit high absorption at certain wavelengths due to strong coupling into lossy waveguide modes. Previously, simulations predicted near-unity, broadband absorption in sparse semiconductor nanowire arrays (<5% fill fraction) with multi-radii and tapered nanowire array designs [1]. Herein, we experimentally demonstrate near-unity broadband absorption in InP nanowire arrays via a scalable, epitaxy-free fabrication method, using nanoimprint lithography and ICP-RIE to define nanowire arrays in bulk InP wafers. In addition to mask pattern design (wire radius and spacing) and etch chemistry (wire taper), appropriate selection of a hard mask for the InP etch is critical to precise dimension control and reproducibility. Polymer-embedded wires are removed from the bulk InP substrate by a mechanical method that facilitates extensive reuse of a single bulk InP wafer to synthesize many polymer-embedded nanowire array thin films. Arrays containing multiple nanowire radii and tapered nanowires were successfully fabricated. For both designs, the polymer-embedded arrays achieved ~90% broadband absorption (λ=400-900 nm) in less than 100 nm planar equivalence of InP. The addition of a silver back reflector increased this broadband absorption to ~95%. The repeatable process of imprinting, etching and peeling to obtain many nanowire arrays from one single wafer represents an economical manufacturing route for high efficiency III-V photovoltaics.


Item Type:Book Section
Related URLs:
URLURL TypeDescription
https://doi.org/10.1117/12.2238450DOIArticle
ORCID:
AuthorORCID
Cheng, Wen-Hui0000-0003-3233-4606
Fountaine, Katherine T.0000-0002-0414-8227
Bukowsky, Colton R.0000-0003-3577-8050
Atwater, Harry A.0000-0001-9435-0201
Additional Information:© 2016 Society of Photo-Optical Instrumentation Engineers (SPIE).
Record Number:CaltechAUTHORS:20180706-091842084
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20180706-091842084
Official Citation:Wen-Hui Cheng, Katherine T. Fountaine, Colton R. Bukowsky, Harry A. Atwater, "Scalable, epitaxy-free fabrication of super-absorbing sparse III-V nanowire arrays for photovoltaic applications (Conference Presentation)", Proc. SPIE 9937, Next Generation Technologies for Solar Energy Conversion VII, 99370D (2 November 2016); doi: 10.1117/12.2238450; https://doi.org/10.1117/12.2238450
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:87585
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:09 Jul 2018 14:40
Last Modified:09 Jul 2018 14:40

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