{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,17]],"date-time":"2026-03-17T04:35:34Z","timestamp":1773722134116,"version":"3.50.1"},"posted":{"date-parts":[[2026,3,17]]},"group-title":"Physical Sciences","reference-count":0,"publisher":"MDPI AG","license":[{"start":{"date-parts":[[2026,3,17]],"date-time":"2026-03-17T00:00:00Z","timestamp":1773705600000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2026,3,14]]},"abstract":"<jats:p>We demonstrate that dopant inhomogeneity strongly suppresses thermal conductivity in Cd\/Eu co-doped, non-polar a-oriented ZnO films grown on r-plane sapphire (Al2O3) by plasma-assisted molecular beam epitaxy. Structural characterization by \u03b8-2\u03b8 XRD confirms a-oriented ZnO without detectable secondary phases. Cross-sectional SEM shows continuous films with well-defined interfaces, and SIMS depth profiling verifies Cd\/Eu incorporation through the film thickness and a sharp Zn\/O drop at the substrate interface. Optical transmittance and Tauc analysis reveal composition-dependent shifts of the absorption edge and band gap. Cross-plane thermal transport was measured at room temperature using frequency-domain photothermal infrared radiometry (PTR) and analyzed by fitting the complex PTR amplitude and phase with a multilayer heat-diffusion model. The extracted thermal conductivity spans ~3.7 - 6.3 Wm-1K-1. The lowest k values correlate with increased defect non-uniformity, consistent with enhanced phonon scattering and reduced effective cross-plane heat transport.<\/jats:p>","DOI":"10.20944\/preprints202603.1194.v1","type":"posted-content","created":{"date-parts":[[2026,3,17]],"date-time":"2026-03-17T02:58:58Z","timestamp":1773716338000},"source":"Crossref","is-referenced-by-count":0,"title":["A Significant Decrease in Thermal Conductivity in Eu- and Cd-Doped ZnO Films due to the Inhomogeneity of Impurities"],"prefix":"10.20944","author":[{"given":"Misha","family":"Khalid","sequence":"first","affiliation":[]},{"given":"Hadiqa","family":"Naaz","sequence":"additional","affiliation":[]},{"given":"Ameneh","family":"Mkaeeli","sequence":"additional","affiliation":[]},{"given":"Ibtasam Bin Abdul","family":"Ghani","sequence":"additional","affiliation":[]},{"given":"Misbah","family":"Aslam","sequence":"additional","affiliation":[]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0385-3124","authenticated-orcid":false,"given":"E.","family":"Przezdziecka","sequence":"additional","affiliation":[]},{"given":"H.","family":"Mubeen","sequence":"additional","affiliation":[]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4984-1519","authenticated-orcid":false,"given":"R.","family":"Jakie\u0142a","sequence":"additional","affiliation":[]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1379-5941","authenticated-orcid":false,"given":"A.","family":"Wierzbicka","sequence":"additional","affiliation":[]},{"given":"B.","family":"Witkowski","sequence":"additional","affiliation":[]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5757-0096","authenticated-orcid":false,"given":"Carlos J.","family":"Tavares","sequence":"additional","affiliation":[]},{"given":"Andreas D.","family":"Wieck","sequence":"additional","affiliation":[]},{"given":"Michal","family":"Pawlak","sequence":"additional","affiliation":[]}],"member":"1968","container-title":[],"original-title":[],"deposited":{"date-parts":[[2026,3,17]],"date-time":"2026-03-17T03:02:41Z","timestamp":1773716561000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.preprints.org\/manuscript\/202603.1194\/v1"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,3,17]]},"references-count":0,"URL":"https:\/\/doi.org\/10.20944\/preprints202603.1194.v1","relation":{},"subject":[],"published":{"date-parts":[[2026,3,17]]},"subtype":"preprint"}}