Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 13: Poster I

HL 13.52: Poster

Monday, March 18, 2024, 15:00–18:00, Poster E

Combined Optical and Atomic Force Microscopic Investigation of Type-I CdSe/CdS Dot-in-Rod Particles with Metal Tips — •Nicklas Giese, Mareike Dittmar, Moritz Wehrmeister, Alf Mews, and Tobias Kipp — Institute of Physical Chemistry, University of Hamburg, 20146 Hamburg, Germany

Semiconductor-metal-hybrid nanostructures can split water and produce hydrogen by illumination, such as dot-in-a-rod particles with a charged metal tip. The understanding and control of the charge transfer processes of these particles is crucial for their further development. We investigate hybrid nanostructures consisting of a CdSe-core/CdS-shell with a metal tip attached. Optical characterization is performed by time-resolved single-particle photoluminescence (PL) spectroscopy. Thereby, the attachment of the metal tip can be correlated with the decrease in quantum yield (QY) and PL lifetime of the semiconductor, giving detailed information on charge-carrier separation. We present an all-in-one setup that combines PL spectroscopy to Kelvin probe force microscopy (KPFM) with simultaneous local illumination of the nanostructure. KPFM is based on an atomic force microscope (AFM) with a conductive cantilever and provides information about the local surface potential by measuring the contact potential difference (CPD) between the sample and the AFM tip. This requires a transparent substrate with a back-gate on which markers can be generated using electron beam- or optical-lithography. The combination of optical and KPFM techniques allows the study of energy-band profiles and the generation of charge-carriers and their concentrations.

Keywords: Kelvin Probe Force Microscopy; Surface Potential; Semiconductor-Metal-Hybrid Structures; Dot in a Rod Particles; Charge Carrier Dynamics