Presentation Details
| W/TiN/n-Si Heterostructures for Schottky Barrier Solar Cells: Utilizing Tungsten as a Carrier Collector for Enhanced Stability and Junction Quality Raid Bader, Haralabos Efstathiadis. Dept.of Nanoscale Science & Engineering, University at Albany, SUNY, Albany, NY, USA |
Abstract
The global pursuit of cost-effective and radiation-hard photovoltaic solutions has entailed a re-evaluation of metal-semiconductor architectures. While Schottky Barrier Solar Cells (SBSCs) offer a simplified, low-thermal-budget alternative to conventional diffused p-n junctions, their performance is historically limited by Fermi level pinning and high interfacial recombination velocities. This work presents the design, fabrication, and characterization of a novel bifacial Tungsten (W)/Titanium Nitride (TiN)/n-Si heterostructure, developed to mitigate these limitations. The device utilizes a PVD-sputtered W/TiN active stack, and a phosphorus spin-on dopant (SOD) diffused Back Surface Field (BSF). Structural analysis (SIMS, XPS, XRD) confirms that a ~4 nm TiN interlayer acts as a critical diffusion barrier, preventing tungsten silicide formation, and effectively unpinning the Fermi level. Electrical characterization yields an effective Schottky barrier height of 0.75 eV and an ideality factor of 1.21, approaching the ideal thermionic emission limit, compared to pure W/Si interfaces (n≈1.45). Under AM1.5G illumination, the unoptimized device achieved a power conversion efficiency (PCE) of 4.3%. Rear-side External Quantum Efficiency (EQE) measurements revealed a peak collection efficiency of 87.2%; this confirms that the junction’s intrinsic quality is excellent and that current losses are primarily optical. These results validate Tungsten as a viable carrier collector when paired with a TiN interlayer, offering a promising pathway for high-stability and radiation-hard architectures suitable for next-generation space photovoltaics.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.