Regensburg 2019 – scientific programme

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O: Fachverband Oberflächenphysik

O 96: Focus Session: Surface Transport at the Atomic Scale

O 96.1: Invited Talk

Friday, April 5, 2019, 10:30–11:00, H15

Electrical transport in semiconductor nanocrystal assemblies and nanocrystal heterostructures — •Bruno Grandidier — IEMN-CNRS, Dept. ISEN Physics, 41 bd Vauban, 59000 Lille, France

Structures consisting of semiconductor nanocrystals are solution-processable materials that are prized for the low-cost and scalability of their fabrication method and their compatibility with flexible, thin-film electronics. Their transport properties are governed by the interfaces between the nanocrystals themselves or the nanocrystals and the supporting semiconductor substrates. Here we will investigate both types of interfaces. We will show how the direct attachment of nanocrystals via chemical bonds between atoms instead of linkage via carbon-based molecules significantly improves the conductivity of two-dimensional nanocrystal arrays. In these systems, charges are coherently delocalized along nanometer-scale segments of nanocrystals ensuring a high THz mobility, while the DC mobility is limited by the absence of long-range order in the arrays. As to solution-based nanocrystal-semiconductor heterostructures, we will show how an initial wet chemical passivation step before the epitaxial growth of the nanocrystals on semiconductor substrates is key not only to produce an atomically sharp crystalline interface, but also to form trap-free interfaces with quality comparable to that grown by molecular beam epitaxy.