Regensburg 2013 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 25: Topical Session: TEM-Symposium - Structure-Property
MM 25.3: Talk
Tuesday, March 12, 2013, 15:45–16:00, H4
Electron tomography and HRTEM investigation of PbSe/carbon nanotube hybrid structures for near-infrared photodetectors — •Benjamin Winter1, Julia Schornbaum2, Benjamin Butz1, Jana Zaumseil2, and Erdmann Spiecker1 — 1Center for Nanoanalysis and Electron Microscopy (CENEM), Materials Science Department VII, University of Erlangen-Nuremberg, 91058 Erlangen, Germany — 2Nanomaterials for Optoelectronics Group, Materials Science Department V, University of Erlangen-Nuremberg, 91058 Erlangen, Germany
Hybrids of single-walled carbon nanotubes (SWNTs) with high charge carrier mobilities and semiconductor quantum dots (QDs) with size-tunable absorption are ideal building blocks for optoelectronic devices. Coupling near-infrared absorbing PbSe QDs to SWNTs transforms the photoexcited states of the QDs into charge separated states. Due to the fast charge transport in SWNTs a dramatic increase of photosensitivity is expected. After the synthesis of the PbSe/SWNT hybrids, Raman spectroscopy indicates that the sp2-carbon lattice of the SWNTs is not chemically modified by the PbSe QDs. This implies that the QDs are attached to the SWNTs without molecular linker and charge transport along the SWNT is not affected. Scanning transmission electron microscopy (STEM) tomography and high-resolution TEM (HRTEM) carried out at 80 kV with an aberration-corrected FEI Titan3 80-300 reveal that the well-defined PbSe QDs partially grow around the SWNT bundles and have a preferred orientation of the {002} lattice planes perpendicular to the longitudinal axis of the SWNT bundles.