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Glass formation in amorphous ZnO films revealed by chip calorimetry
摘要： 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 (cid:1) 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 (cid:3)C have a room temperature thermal conductivity of (cid:1) 1:03–1:4 W m(cid:4)1 K(cid:4)1 (consistent with recent ab initio estimates) with supporting evidence of a structural relaxation near TG consistently observed in both electronic and thermal conductivity.
关键词： semiconductor properties,amorphous ZnO films,glass formation,chip calorimetry,flash drying
更新于2025-09-23 15:19:57
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Amorphous ZnO/PbS quantum dots heterojunction for efficient responsivity broadband photodetectors
摘要： The integration of lead sulfide quantum dots (QDs) with high conductivity material that is compatible with a scalable fabrication is an important route for the applications of QDs based photodetectors. Herein, we firstly developed a broadband photodetector by combining amorphous ZnO and PbS QDs forming a heterojunction structure. The photodetector showed detectivities up to 7.9x1012 jones and 4.1x1011 jones under 640 nm and 1310 nm illumination, respectively. The role of oxygen background pressure on the electronic structure of ZnO films grown by pulsed laser deposition was systematically studied, and it was found to play an important role on the conductivity, associated to the variation of oxygen vacancy concentration. By increasing the oxygen vacancy concentration, the electron mobility of amorphous ZnO layers dramatically increased and work function decreased, which were beneficial for the photocurrent enhancement of ZnO/PbS QDs photodetectors. Our results provide a simple and highly scalable approach to develop broadband photodetectors with high performance.
关键词： oxygen vacancy,amorphous ZnO,broadband photodetector,mobility,heterojunction
更新于2025-09-16 10:30:52