In this work, we utilize the high heating/cooling rates of chip calorimetry to perform in situ annealing of an inkjet-printed zinc oxide solgel ink consisting of zinc acetate, 2-methoxyethanol, and monoethanolamine and directly observe the thermodynamic signatures of its corresponding structural phase transformations. We find that rapid solvent removal achieved by annealing above the boiling point of the solvent, similar to an industrial drying technique known as flash drying, induces the formation of ≈ 98 % amorphous zinc oxide films having an unprecedented, largely pronounced glass transition while retaining its semiconductor properties evidenced by field-effect transistor measurements. Thin-films produced at comparable heating rates to those used for calorimetry experiments are used to corroborate these findings using independent measurements. Prepared films exhibit a clear amorphous halo centered about the three most prominent Bragg positions of the wurtzite phase of ZnO and remain thermally stable against crystallization until 250 ° C have a room temperature thermal conductivity of ≈ 1.03 - 1.4 W m - 1 K - 1 (consistent with recent ab initio estimates) with supporting evidence of a structural relaxation near T G consistently observed in both electronic and thermal conductivity.
Bibliographical noteKAUST Repository Item: Exported on 2021-02-16
Acknowledged KAUST grant number(s): OSR-2016-CRG5-3029-01
Acknowledgements: This work was performed at the Georgia Institute of Technology, with support from both the School of Chemistry and Biochemistry and the Department of Materials Science and Engineering, under the management of Professor Natalie Stingelin and Professor Carlos Silva. This work was performed in part at the Georgia Tech Institute for Electronics and Nanotechnology, a member of the National Nanotechnology Coordinated Infrastructure, which is supported by the National Science Foundation (NSF) (Grant No. ECCS-1542174). We acknowledge the U.S. National Science Foundation for support through the DMREF program (No. DMR-1729737) and the EAGER program (No. DMR-1838276). We also acknowledge funding by the King Abdullah University of Science and Technology (KAUST) via a KAUST Competitive Research Grant (No. OSR-2016-CRG5-3029-01). The authors declare no competing interests. The data that support the findings of this study are available from the corresponding authors upon reasonable request.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.