Regensburg 2019 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 16: Focus Session: Oxide Semiconductors for Novel Devices III

HL 16.2: Vortrag

Dienstag, 2. April 2019, 09:45–10:00, H34

Protective coatings for photoelectrochemical applications — •David Silva, Oliver Bienek, and Ian Sharp — Technische Universität München, Walter Schottky Institut, Munich, Germany

Several photoactive semiconductor materials have been reported to yield promising energy conversion efficiencies in photocatalytic applications. However, the harsh chemical environments in which photoelectrochemical conversion (PEC) systems operate causes accelerated (photo) corrosion of many semiconductor light absorbers. In recent years, this issue has been mitigated via the application of conformal thin film protection layers, such as TiO₂, deposited via atomic layer deposition (ALD). However, interfacial charge transfer pathways, as well as the nature and impact of electronically active defects in highly disordered protection layers, remain poorly understood. Here, we report on optical characterization of these films using photothermal deflection spectroscopy (PDS), combined with complementary photocurrent measurements and surface photovoltage spectroscopy (SPS). Together, these measurements provide a deeper understanding of defect properties of these materials and their roles in photoelectrochemical energy conversion. Impacts of heterojunction energetics are analyzed by extending these approaches to model systems comprising TiO₂ on GaN substrates.