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 “n” 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

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