High resolution x-ray diffraction study of the substrate temperature and thickness dependent microstructure of reactively sputtered epitaxial ZnO films

Handle URI:
http://hdl.handle.net/10754/625423
Title:
High resolution x-ray diffraction study of the substrate temperature and thickness dependent microstructure of reactively sputtered epitaxial ZnO films
Authors:
Singh, Devendra; Kumar, Ravi; Ganguli, Tapas; Major, Syed S
Abstract:
Epitaxial ZnO films were grown on c-sapphire by reactive sputtering of zinc target in Ar-O2 mixture. High resolution X-ray diffraction measurements were carried out to obtain lateral and vertical coherence lengths, crystallite tilt and twist, micro-strain and densities of screw and edge dislocations in epilayers of different thickness (25 - 200 nm) and those grown at different temperatures (100 - 500 °C). phgr-scans indicate epitaxial growth in all the cases, although epilayers grown at lower substrate temperatures (100 °C and 200 °C) and those of smaller thickness (25 nm and 50 nm) display inferior microstructural parameters. This is attributed to the dominant presence of initially grown strained 2D layer and subsequent transition to an energetically favorable mode. With increase in substrate temperature, the transition shifts to lower thickness and growth takes place through the formation of 2D platelets with intermediate strain, over which 3D islands grow. Consequently, 100 nm thick epilayers grown at 300 °C display the best microstructural parameters (micro-strain ~1.2 x 10-3, screw and edge dislocation densities ~1.5 x 1010 cm-2 and ~2.3 x 1011 cm-2, respectively). A marginal degradation of microstructural parameters is seen in epilayers grown at higher substrate temperatures, due to the dominance of 3D hillock type growth.
KAUST Department:
Physical Sciences and Engineering (PSE) Division
Citation:
Singh D, Kumar R, Ganguli T, Major SS (2017) High resolution x-ray diffraction study of the substrate temperature and thickness dependent microstructure of reactively sputtered epitaxial ZnO films. Materials Research Express. Available: http://dx.doi.org/10.1088/2053-1591/aa885e.
Publisher:
IOP Publishing
Journal:
Materials Research Express
Issue Date:
24-Aug-2017
DOI:
10.1088/2053-1591/aa885e
Type:
Article
ISSN:
2053-1591
Sponsors:
The authors would like to thank Prof. Raman Srinivasa for his keen interest in this work and helpful discussions.
Additional Links:
http://iopscience.iop.org/article/10.1088/2053-1591/aa885e
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorSingh, Devendraen
dc.contributor.authorKumar, Ravien
dc.contributor.authorGanguli, Tapasen
dc.contributor.authorMajor, Syed Sen
dc.date.accessioned2017-08-30T11:40:25Z-
dc.date.available2017-08-30T11:40:25Z-
dc.date.issued2017-08-24en
dc.identifier.citationSingh D, Kumar R, Ganguli T, Major SS (2017) High resolution x-ray diffraction study of the substrate temperature and thickness dependent microstructure of reactively sputtered epitaxial ZnO films. Materials Research Express. Available: http://dx.doi.org/10.1088/2053-1591/aa885e.en
dc.identifier.issn2053-1591en
dc.identifier.doi10.1088/2053-1591/aa885een
dc.identifier.urihttp://hdl.handle.net/10754/625423-
dc.description.abstractEpitaxial ZnO films were grown on c-sapphire by reactive sputtering of zinc target in Ar-O2 mixture. High resolution X-ray diffraction measurements were carried out to obtain lateral and vertical coherence lengths, crystallite tilt and twist, micro-strain and densities of screw and edge dislocations in epilayers of different thickness (25 - 200 nm) and those grown at different temperatures (100 - 500 °C). phgr-scans indicate epitaxial growth in all the cases, although epilayers grown at lower substrate temperatures (100 °C and 200 °C) and those of smaller thickness (25 nm and 50 nm) display inferior microstructural parameters. This is attributed to the dominant presence of initially grown strained 2D layer and subsequent transition to an energetically favorable mode. With increase in substrate temperature, the transition shifts to lower thickness and growth takes place through the formation of 2D platelets with intermediate strain, over which 3D islands grow. Consequently, 100 nm thick epilayers grown at 300 °C display the best microstructural parameters (micro-strain ~1.2 x 10-3, screw and edge dislocation densities ~1.5 x 1010 cm-2 and ~2.3 x 1011 cm-2, respectively). A marginal degradation of microstructural parameters is seen in epilayers grown at higher substrate temperatures, due to the dominance of 3D hillock type growth.en
dc.description.sponsorshipThe authors would like to thank Prof. Raman Srinivasa for his keen interest in this work and helpful discussions.en
dc.publisherIOP Publishingen
dc.relation.urlhttp://iopscience.iop.org/article/10.1088/2053-1591/aa885een
dc.rightsThis is an author-created, un-copyedited version of an article accepted for publication/published in Materials Research Express. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at http://doi.org/10.1088/2053-1591/aa885e. As the Version of Record of this article is going to be/has been published on a subscription basis, this Accepted Manuscript will be available for reuse under a CC BY-NC-ND 3.0 licence after a 12 month embargo period.en
dc.titleHigh resolution x-ray diffraction study of the substrate temperature and thickness dependent microstructure of reactively sputtered epitaxial ZnO filmsen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalMaterials Research Expressen
dc.eprint.versionPost-printen
dc.contributor.institutionMaterials Science Section, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh, INDIAen
dc.contributor.institutionSynchrotron Utilization Section, Raja Ramanna Centre for Advanced Technology, Indore, INDIAen
dc.contributor.institutionDepartment of Physics, Indian Institute of Technology Bombay, Mumbai, Maharashtra, INDIAen
kaust.authorSingh, Devendraen
All Items in KAUST are protected by copyright, with all rights reserved, unless otherwise indicated.