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dc.contributor.advisorOhno, Timothy R.
dc.contributor.advisorGessert, Timothy A.
dc.contributor.authorFaulkner, Brooke R.
dc.date.accessioned2016-02-22T20:20:28Z
dc.date.accessioned2022-02-03T12:57:59Z
dc.date.available2016-02-22T20:20:28Z
dc.date.available2022-02-03T12:57:59Z
dc.date.issued2016
dc.identifierT 7994
dc.identifier.urihttps://hdl.handle.net/11124/170055
dc.description2016 Spring.
dc.descriptionIncludes color illustrations.
dc.descriptionIncludes bibliographical references.
dc.description.abstractA commonly produced commercial thin-film solar cell consists of cadmium telluride (CdTe) as the p-type material, and cadmium sulfide (CdS) as the n-type. High-performance CdS/CdTe thin-film photovoltaic (PV) devices can be produced by incorporating a copper-dopped zinc telluride (ZnTe:Cu) interface layer between the CdTe absorber and a titanium (Ti) outer metal contact. This contacting process not only enable low-resistance tunneling between the ZnTe:Cu and Ti but allows Cu diffusion into the CdTe, increasing the net-acceptor concentration, leading to higher efficiency cells. Thin-film ZnTe:Cu is deposited by sputtering, a process where a solid material target is hit by energetic particles so that atoms are ejected from the target onto the substrate. Although the contact demonstrates both high performance and stability, recent studies suggest that oxygen incorporated into the ZnTe:Cu during sputtering process can be detrimental to device performance. One interpretation of this observation is that oxygen bonds with Cu, and reduces Cu diffusion into the CdTe layer. We first investigated how oxygen incorporation from various ZnTe:Cu sputtering targets affect film properties and their resulting device performance by exploring different target manufacturing processes that have the potential to reduce oxygen content in films. Initial materials analysis suggests targets produced from raw elements (Zn, Te, and Cu) rather than compounds (ZnTe and Cu) causes formation of a Cu2Te phase in the powders used to make the targets, leading to higher-density targets, which also produce films that appear visually more transparent. Analysis of ZnTe:Cu films include compositional, optical, structural, electrical, characterization. We also look at how different target manufacturing techniques affect device performance. Furthermore, we explored how varying deposition parameters, such as substrate temperature and sputtering ambient affect film properties. We study how the optical band gap, Eg, and Urbach energy, EU, which is the width of the localized states that tail into the band gap, from optical spectra of the ZnTe:Cu films due to change in compositional and structural properties from varying deposition parameters.
dc.format.mediumborn digital
dc.format.mediummasters theses
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado School of Mines. Arthur Lakes Library
dc.relation.ispartof2016 - Mines Theses & Dissertations
dc.rightsCopyright of the original work is retained by the author.
dc.subjectCdTe
dc.subjectcontact interface layer
dc.subjectCu-doped ZnTe
dc.subjectphotovoltaic
dc.subjectsputtering target
dc.subjectZnTe:Cu
dc.titleVariation of ZnTe:Cu sputtering target preparation and impacts on film properties and CdS/CdTe solar cell performance
dc.typeText
dc.contributor.committeememberBeach, Joseph D.
dc.contributor.committeememberBurst, James M.
thesis.degree.nameMaster of Science (M.S.)
thesis.degree.levelMasters
thesis.degree.disciplinePhysics
thesis.degree.grantorColorado School of Mines


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