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Thickness uniformity and optical/structural evaluation of RF sputtered ZnO thin films for solar cell and other device applications

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Abstract

Spatial uniformity in thickness and other characteristics over the surface of thin films plays a fundamental role in characterization and device fabrication particularly in the solar cells. We report an investigation in the preparation of zinc oxide (ZnO) thin film on sapphire substrate by RF magnetron sputtering and characterization by spectral reflectance, photoluminescence, transmittance, and atomic force microscopy measurements. Surface of the film is spatially analyzed and a comparison is established with the previously reported results of metal organic chemical vapor deposition (MOCVD) grown ZnO film. Results show that ZnO films prepared by sputtering technique are superior in thickness uniformity for practical applications. Optical quality of the films prepared by sputtering is similar or even shows better quality compared to the films grown by MOCVD. Furthermore, the importance of film thickness uniformity in particular with reference to the solar cell performance is discussed that, so far, could not draw adequate attention from the research community.

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Acknowledgements

We are thankful to the reviewers of this paper for their help to improve the quality and clarity of presentation. We are grateful to Drs. Edward Stokes and Young Zhang (both from UNCC) for letting us use their equipment to measure thickness, transmission, and photoluminescence. Babar Hussain is thankful to Dr. Michael Fiddy (UNCC) for useful discussions and also to Dr. Lou Deguzman and Hanin Elathram (both from UNCC) for their technical help. This work has been partially funded by College of Engineering at UNC Charlotte.

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Authors and Affiliations

  1. College of Engineering, Department of Electrical and Computer Engineering, University of North Carolina at Charlotte, Charlotte, NC, 28223, USA

    Thiara Ortiz, Crystal Conde & Babar Hussain

  2. National Institute of Lasers and Optronics, Nilore, 45650, Islamabad, Pakistan

    Taj M. Khan & Babar Hussain

  3. School of Physics, Trinity College Dublin (TCD), Dublin, Ireland

    Taj M. Khan

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  1. Thiara Ortiz
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  2. Crystal Conde
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  3. Taj M. Khan
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  4. Babar Hussain
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Correspondence to Babar Hussain.

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Ortiz, T., Conde, C., Khan, T.M. et al. Thickness uniformity and optical/structural evaluation of RF sputtered ZnO thin films for solar cell and other device applications. Appl. Phys. A 123, 280 (2017). https://doi.org/10.1007/s00339-017-0909-2

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  • DOI: https://doi.org/10.1007/s00339-017-0909-2

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