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The microstructure of thin film CdTe absorber layers deposited by pulsed dc magnetron sputtering

conference contribution
posted on 04.08.2017, 12:17 authored by Piotr Kaminski, Ali AbbasAli Abbas, Sibel Yilmaz, Michael WallsMichael Walls
High rate pulsed DC magnetron sputtering has been used to fabricate thin film CdTe photovoltaic devices. Fabrication of thin film photovoltaic devices using magnetron sputtering has the advantages of excellent coating uniformity and use of lower substrate temperatures during deposition. The CdTe and CdS layers were deposited from compound targets. The substrates were held at 200ºC during deposition, a process condition previously found to minimize the stress in the coatings. The devices were deposited using rotation to provide coatings with exceptionally uniformity. This enabled the CdTe absorber thickness to be reduced to ~1μm. The microstructure of the as-deposited material is dense and columnar. The cadmium chloride activation treatment results in an increase in grain size and it also removes the majority of planar defects. However, void formation has been observed which becomes more severe with increasing time of the activation process. In some cases the void formation leads to catastrophic failure and delamination at the CdS/CdTe junction. The microstructure of the films has been characterized before and after activation using a number of techniques including High Resolution Transmission Electron Microscopy of device cross-sections. The observations made have been correlated to device performance.

Funding

The authors are grateful to the EPSRC Supergen SuperSolar Hub for funding. They are also grateful for ongoing collaboration with the NSF Industrial/UCRC for Next Generation Photovoltaics at Colorado State University.

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Published in

43rd IEEE Photovoltiacs Specialist Conference (PVSC) 2016

Pages

1564 - 1569 (5)

Citation

KAMINSKI, P.M. ... et al, 2016. The microstructure of thin film CdTe absorber layers deposited by pulsed dc magnetron sputtering. Presented at the 43rd IEEE Photovoltiacs Specialist Conference (PVSC) 2016, Portland, OR, USA, 5th-10th June 2016, pp. 1564-1569.

Publisher

© IEEE

Version

VoR (Version of Record)

Acceptance date

10/06/2016

Publication date

2016

Notes

This paper is closed access.

ISBN

9781509027248

Language

en

Location

Portland, OR