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Title:
 
Diameter Reduction of Silicon Nanowires Using Ozone Oxidation Method for the Application to the All-Silicon Tandem Solar Cells
 
Author(s):
 
Y. Kurokawa, E. Ishida, Y. Yamada, S. Kato, A. Yamada
 
Keywords:
 
Passivation, Quantum Well, Tandem, Silicon Solar Cell(s), High Efficiency
 
Topic:
 
NEW MATERIALS AND CONCEPTS FOR SOLAR CELLS AND MODULES
Subtopic: New Materials and Concepts for Cells
Event: 29th European Photovoltaic Solar Energy Conference and Exhibition
Session: 1BV.7.45
 
Pages:
 
298 - 302
ISBN: 3-936338-34-5
Paper DOI: 10.4229/EUPVSEC20142014-1BV.7.45
 
Price:
 
 
0,00 EUR
 
Document(s): paper, poster
 

Abstract/Summary:


For the purpose of the application to the top cell in all-silicon tandem solar cells, we have fabricated silicon nanowire arrays using metal assisted chemical etching with silica nanoparticles (MACES) method. In this method, the diameter of SiNWs can be controlled to around 30 nm. However, to control the bandgap of SiNWs using the quantum size effect, the diameter has to be less than 5 nm. In this study, to reduce the diameter, we tried ozone thermal oxidation of SiNWs. Ozone enables us oxidation at lower temperature than oxygen. SiNW arrays fabricated by MACES were oxidized under 24.9wt% ozone at 700 °C for 3 hours. From an energy dispersive x-ray spectroscopy (EDS) mapping, it was confirmed that the oxygen concentration was increased in the whole of SiNW arrays after the oxidation. Cross-sectional transmission electron microscopy (TEM) image showed that the silicon-part-diameter of a SiNW was reduced to about 5 nm around the top of the SiNW. Therefore, ozone oxidation process is promising method to reduce the diameter of SiNWs at lower temperature.