Dresden 2026 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 7: Thermoelectric and Phase Change Materials

DS 7.3: Vortrag

Dienstag, 10. März 2026, 10:30–10:45, REC/B214

Understanding Charge Transport in ZnO Quantum Dots Through Combined Thermoelectric and High-Field Measurements — •Henrik Holzhauser, Morteza Shokrani, and Martijn Kemerink — IMSEAM, Heidelberg University, Germany

ZnO Quantum Dot (QD) solids are an attractive material for a wide range of applications. ZnO QDs also make an excellent model system for QD solid in general owing to the ability to tune the effective diameter of ZnO QD via UV illumination, and the effective electronic localization length via ligands. The charge transport in QD solids is typically explained as thermally activated tunnelling or hopping between the localized states of individual QDs. As such, the electric conductivity is both electric field and temperature dependent. In comparison, the Seebeck effect in QD solids, especially in connection with the electrical conductivity, is not as precisely understood. Here, we combine measurements of the Seebeck coefficient for various ZnO QDs with electric field- and temperature-dependent conductivity measurements, all performed at lattice temperatures ranging from 100 to 300K. We used bare ZnO QDs and ZnO QDs with ligands of various lengths and measured all QD solids at multiple UV-induced effective diameters. The wide range of experiments allows us to obtain a comprehensive understanding of the dominant mechanisms and the characteristic energy and length scales in the system. We find that transport is dominated by energetic disorder resulting from a diameter-dependent charging energy, in combination with an effective localization energy that reflects both wavefunction decay and morphology.

Keywords: ZnO Quantum Dots; Seebeck; Conductivity; Quantum Dot solids; thermally activated tunnelling