Regensburg 2019 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 47: Quantum dots and wires: Optical properties II
HL 47.13: Talk
Friday, April 5, 2019, 12:45–13:00, H34
Synthesis and Characterization of Lead Chalcogenide Nanocrystals for Short-Wavelength Infrared Photodetectors — •Martin Sarott1,2, Tianshuo Zhao2, and Cherie Kagan2 — 1Laboratory of Multifunctional Ferroic Materials (M. Fiebig), ETH Zurich, Switzerland — 2Department of Materials Science and Engineering, University of Pennsylvania, USA
Recent advances in the characterization and synthesis of solution-processable semiconductor nanocrystals (NCs) have increased the interest in this class of materials for optoelectronic device applications including solar cells, light-emitting diodes, and photodetectors. In particular, lead chalcogenide NCs are promising candidates with a broadly tuneable spectral response from visible (VIS) to infrared (IR) depending on the NC size. In this study, we prepare PbS, PbSe, and PbTe NCs with a first excitonic absorption peak in the short-wavelength infrared range at 1.55um. For a variety of ligand chemistries, charge transport and doping properties of NC films are measured on a field-effect transistor (FET) geometry. Vertically stacked p-n and p-i-n heterojunction photodiodes are fabricated using an n-type ZnO film as electron transport layer. Current-voltage characteristics reveal that the degree of rectification, noise, and dark current level strongly depend on the choice of ligand, air-exposure, and electron blocking layers (MoO3) within the diode stack.