Characterization of &#946;-FeSi<sub>2</sub> films as a novel solar cell semiconductor

Yasuhiro Fukuzawa; Teruhisa Ootsuka; Naotaka Otogawa; Hironori Abe; Yasuhiko Nakayama; Yunosuke Makita

doi:10.1117/12.663892

12 May 2006 Characterization of β-FeSi₂ films as a novel solar cell semiconductor

Yasuhiro Fukuzawa, Teruhisa Ootsuka, Naotaka Otogawa, Hironori Abe, Yasuhiko Nakayama, Yunosuke Makita

Proceedings Volume 6197, Photonics for Solar Energy Systems; 61970N (2006) https://doi.org/10.1117/12.663892
Event: SPIE Photonics Europe, 2006, Strasbourg, France

Abstract

β-FeSi₂ is an attractive semiconductor owing to its extremely high optical absorption coefficient (α>10⁵ cm^-1), and is expected to be an ideal semiconductor as a thin film solar cell. For solar cell use, to prepare high quality β-FeSi₂ films holding a desired Fe/Si ratio, we chose two methods; one is a molecular beam epitaxy (MBE) method in which Fe and Si were evaporated by using normal Knudsen cells, and occasionally by e-gun for Si. Another one is the facing-target sputtering (FTS) method in which deposition of β-FeSi₂ films is made on Si substrate that is placed out of gas plasma cloud. In both methods to obtain β-FeSi₂ films with a tuned Fe/Si ratio, Fe/Si super lattice was fabricated by varying Fe and Si deposition thickness. Results showed significant in- and out-diffusion of host Fe and Si atoms at the interface of Si substrates into β-FeSi₂ layers. It was experimentally demonstrated that this diffusion can be suppressed by the formation of template layer between the epitaxial β-FeSi₂ layer and the substrate. The template layer was prepared by reactive deposition epitaxy (RDE) method. By fixing the Fe/Si ratio as precisely as possible at 1/2, systematic doping experiments of acceptor (Ga and B) and donor (As) impurities into β-FeSi₂ were carried out. Systematical changes of electron and hole carrier concentration in these samples along variation of incorporated impurities were observed through Hall effect measurements. Residual carrier concentrations can be ascribed to not only the remaining undesired impurities contained in source materials but also to a variety of point defects mainly produced by the uncontrolled stoichiometry. A preliminary structure of n-β-FeSi₂/p-Si used as a solar cell indicated a conversion efficiency of 3.7%.

Citation Download Citation

Yasuhiro Fukuzawa, Teruhisa Ootsuka, Naotaka Otogawa, Hironori Abe, Yasuhiko Nakayama, and Yunosuke Makita "Characterization of β-FeSi₂ films as a novel solar cell semiconductor", Proc. SPIE 6197, Photonics for Solar Energy Systems, 61970N (12 May 2006); https://doi.org/10.1117/12.663892

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available