Title

Optical And Microstructural Properties Of Tio2 Anti-Reflection Coatings Deposited Via In-Line Apcvd

Keywords

Aluminum oxide; Anti-reflection coatings; APCVD; Optics; Photovoltaic cells; Silicon; Titanium oxide

Abstract

Titanium oxide (TiO2) was a commonly used anti-reflection coating (ARC) in the past, but has been displaced by silicon nitride (SiN x) due to its ability to both passivate n+ emitters and provide the appropriate optical properties required for effective ARCs (refractive index, transparency, stability over time). However, with growing interest in n-type wafers, which feature p+ emitters, and the inability of SiNx to provide effective field-effect passivation for p-type materials, other passivation materials are being actively investigated by the photovoltaics (PV) R&D community. Aluminum oxide (AlOx) is one of such materials due to its ability to provide both low interface defect densities and sufficient negative fixed charge. Although AlOx is transparent and stable, the refractive index isn't ideally matched for a Si/air or Si/encapsulant interface. To circumvent the poor index matching, it has been shown that a multi-layer passivation/ARC stack is possible, allowing for both good passivation and ideal refractive index and sparking a renewed interest in TiO2. The high quality passivation is obtained by using a thin passivation layer (< 20 nm) like AlOx, followed by a low cost optical material such as TiO 2 with a proper refractive index for an ARC. This paper addresses the optical and microstructural properties of TiO2 films deposited at various temperatures using an in-line atmospheric chemical vapor deposition system (APCVD). The TiO2 films are investigated by spectroscopic ellipsometry, reflectance spectroscopy and cross-sectional TEM. Additionally, experimental results for the ARC performance of multi-layer ARC structures featuring AlOx/TiO2 are presented. © 2013 IEEE.

Publication Date

1-1-2013

Publication Title

Conference Record of the IEEE Photovoltaic Specialists Conference

Number of Pages

-

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.1109/PVSC.2013.6744361

Socpus ID

84896469993 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84896469993

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