Regensburg 2004 – wissenschaftliches Programm

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PV: Plenarvorträge

PV XIII

PV XIII: Plenarvortrag

Freitag, 12. März 2004, 08:30–09:15, H1

Trillions of quantum dots, Fingerprints, Nanolithography with diblock copolymers, Annealing and alignment of striped and hexatic phases — •Paul Chaikin — Dept. of Physics, Princeton University, Princeton, NJ 08544

We have been using monolayer films of cylindrical and spherical phase diblock copolymers to make ultradense patterns over wide areas on arbitrary substrates. For example we cover a three inch wafer with ∼ 3 trillion posts, holes, etc. spaced by ∼ 25nm, to make quantum dots (for semiconductor lasers), metal particles and wires (for UV polarizers) … In trying to understand how the polymer patterns order we have used atomic force microscopy (AFM) to image the cylindrical phase which lies flat on a substrate. The patterns look like fingerprints and Benard rolls and the coarsening (annealing) law we observe is t^(1/4) as in previous studies of these striped phases. This law remained unexplained for decades. However, guided by previous studies of fingerprints and their defects we made time lapse AFM movies which show that the annealing dynamics is governed by the attraction of disclination PAIRS, quadrupoles, rather than simple +/– annihilation. This directly provides an explanation for the alignment of the striped patterns as a function of time. Thus these systems, while aimed at technological and fundamental electronic applications are also ideal materials for studying the dynamics and thermodynamics of ordering in two dimensions. Recently we have shown that simple shear can lead to ordering of these nanometer patterns on centimeter and larger scales.