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Abstract: In most cases, III–V compounds form a crystal structure, which is stable under certain experimental conditions. Meantime crystal phase of III–V nanowires may differ from the stable phase of bulk structures. In this work, we show that the elastic stress could be the sole factor responsible for nanowire growth in the metastable phase. Depending on the experimental conditions of GaP nanowire growth, the elastic stress contribution to nucleation barrier can be greater than the difference in the energy of the formation of the cubic and hexagonal phase, and thus, it causes the growth in metastable wurtzite crystal phase.

The structural properties of GaAs and AlGaAs nanowhiskers (NWs) grown by molecular beam epitaxy (MBE) on a GaAs substrate surfaces of different crystallographic orientations are investigated. Under optimal growth conditions, the aspect ratio of MBE grown GaAs NWs is higher than 100. The maximum length of NWs is several times (up to 10) larger than the effective thickness of deposited GaAs. A kinetic model of the diffusion-induced NW growth is used to predict the dependence of NW length on the technologically controlled MBE growth conditions. The obtained results demonstrate that the NW growth in our experiments is mainly controlled by the adatom diffusion towards their tip rather than by the conventional adsorption controlled vapor–liquid–solid mechanism. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The spectral analysis of the Schrödinger operator on cubic lattice type graphs is developed. Similarly to the quantum mechanical tight-binding approximation, using the well known concept of the Dirichlet-to-Neumann map, asymptotic formulae for localized negative spectral bands of the Schrödinger operator on a periodic metric graph are established. The results are illustrated by numerical calculations.