Investigations of Electronic Structure of Bare and Passivated Nanocrystalline Silicon Clusters and their Transport Properties
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Date
2009-06
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Addis Ababa Universty
Abstract
Silicon low dimensional structures are found to be extremely stable in comparison to bulk
silicon along with variety of interesting electronic properties. They are established as potential
candidates for various promising applications in advanced nano-electronics devices especially
in a nano-switch to be specific. Here we are presenting our most recent and most detailed
results for electronic and transport properties of ground-state structures of Sin, SinH and SinO
clusters using DFT- LDA-NEGF simulations. From our present set of studies, a high degree of
structural stability is observed in very small Sin nanoclusters of various sizes; n = 4, 6, 7 and 8.
Amongst several diverse and stable clusters, the Si6 is found to possess a maximum stability.
The energy gaps in between LUMO-HOMO of Si clusters are also found to be decreasing with
the ānā in accordance with general principles of a quantum confinement with an exception of
the Si6 cluster. Density of states spectra (DOS), transmission spectrum (TS) and currentvoltage
(I-V) calculations are also preformed. Various TS spectra results are mostly discussed
in contest to charge transfer phenomena, states injection in between various components of the
nanodevices and their ensuing effects on the nanoswitching. We have also ascertained
increased cluster stability with the passivation and the presence of a significant contributing
states at fermi energies in nano devices that are made up of these clusters. A novel
phenomenon of a negative differential resistance becomes pragmatic in I-V curves of these
samples and it is discussed in relation to the Q-confinement induced singularities among the
concerned nanostructures. I-V characteristics curve of a device ZGNR/Si8H/ZGNR shows
strong nonlinearity as a result it can be fruitfully deployed for the nano-switch. Various lurid
prospects of nano-swtcing using Sin nanoclusters are also conferred in the present work.
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Silicon