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HL: Halbleiterphysik

HL 49: Poster II

HL 49.74: Poster

Donnerstag, 27. März 2003, 16:30–19:00, HSZ/P2

A new InGaAs bond-order potential for the investigation of kinetic effects in quantum dot growth — •Thomas Hammerschmidt, Peter Kratzer, and Matthias Scheffler — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin-Dahlem

A thorough understanding of the experimentally observed shape of InAs quantum dots (QD) calls for non-equilibrium simulations that take kinetic growth-effects into account.

We present a new analytical potential for InGaAs that is based on the bond-order scheme of Abell and Tersoff to model the covalent bonding character. It is derived from previously published potentials and modified to capture reconstructed GaAs(001)-surfaces more accurately and to improve the predictions for InAs surfaces and small clusters of Ga, As and In atoms thereby preserving the previous adaptions to bulk phases.

The potential allows for reliable calculations of elastic strain effects in capped and uncapped QD, where atoms are 4-fold or 3-fold coordinated. For situations with low atomic coordination, as occur in surface-diffusion of Ga and In adatoms, we apply the potential to study the efficiency of different algorithms to search for transition states.

We compare our results with recent density functional calculations.