Berlin 2018 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 33: Poster Session III

HL 33.30: Poster

Mittwoch, 14. März 2018, 17:30–19:30, Poster F

Transparent UV-active solar cells based on NiO/ZnO heterostructures: Supression of interface recombination currents — •Robert Karsthof, Holger von Wenckstern, and Marius Grundmann — Felix-Bloch-Institut für Festkörperphysik, Universität Leipzig, Linnéstraße 5, 04103 Leipzig, Germany

Visible-light-transparent photovoltaic cells open new fields of application for solar cells, such as energy harvesting on windows, glass roofs or displays of mobile devices. It has been shown [1] that p-NiO/n-ZnO heterojunctions show photovoltaic activity in the UV spectral range. They suffer, however, from a severe illumination-induced increase of the carrier recombination rate at the type-II heterointerface. Because of the strong offsets in valence and conduction bands of the heterostructure, recombination through interface gap states is the dominating transport mechanism under both dark and illuminated conditions.
In this work, we studied the effect of the inclusion of a few-nm-thin insulating layer of HfO₂ between NiO and ZnO, aiming at a suppressed interface recombination by widening the interface gap and reducing the density of states within it. At the same time, it should allow an unhindered transport of photogenerated carriers across.
NiO and ZnO layers were grown by pulsed laser deposition, the HfO₂ buffer layers were deposited by RF sputtering. Device characterization was done by current-voltage, capacitance-voltage and quantum efficiency measurements as well as carrier collection analysis.

[1] R. Karsthof, H. von Wenckstern, M. Grundmann: J. Vac. Sci. Technol. B 34, 04J107 (2016)