Multiscale Self-Assembly of Silicon Quantum Dots into an Anisotropic Three-Dimensional Random Network
mediaposted on 11.02.2016, 00:00 by Serim Ilday, F. Ömer Ilday, René Hübner, Ty J. Prosa, Isabelle Martin, Gizem Nogay, Ismail Kabacelik, Zoltan Mics, Mischa Bonn, Dmitry Turchinovich, Hande Toffoli, Daniele Toffoli, David Friedrich, Bernd Schmidt, Karl-Heinz Heinig, Rasit Turan
Multiscale self-assembly is ubiquitous in nature but its deliberate use to synthesize multifunctional three-dimensional materials remains rare, partly due to the notoriously difficult problem of controlling topology from atomic to macroscopic scales to obtain intended material properties. Here, we propose a simple, modular, noncolloidal methodology that is based on exploiting universality in stochastic growth dynamics and driving the growth process under far-from-equilibrium conditions toward a preplanned structure. As proof of principle, we demonstrate a confined-but-connected solid structure, comprising an anisotropic random network of silicon quantum-dots that hierarchically self-assembles from the atomic to the microscopic scales. First, quantum-dots form to subsequently interconnect without inflating their diameters to form a random network, and this network then grows in a preferential direction to form undulated and branching nanowire-like structures. This specific topology simultaneously achieves two scale-dependent features, which were previously thought to be mutually exclusive: good electrical conduction on the microscale and a bandgap tunable over a range of energies on the nanoscale.