Synthesis Of Bicyclic Silane And Study On Its Single Molecule Conductivity

Bulk silicon, the bedrock of information technology, consists of the deceptively simple electronic structure of just Si-Si σ bonds. Diamond has the same lattice structure as silicon, yet the two materials have dramatically different electronic properties. Molecular forms are the essential components of the bulk semiconductor. Moreover, as silicon electronics continues to scale to smaller length scales the connection between molecular silicon and silicon from bulk single crystals will become more explicit. In silicon electronics, conductive path and strain of the molecular has been found to an important parameter to insert and control to maximize performance.This thesis focuses on bicyclosilanes. There are many of these types of structures that have been prepared. For example bicyclo[2.2.1]silane, bicyclo[2.2.2]sialne, bicyclo[1.1.1]silane. The important point in context of this thesis is that they will be functionalized allowing them to be incorporated in molecular electronic devices for transport measurements. The scanning tunneling microscope based break-junction technique(STM-BJ) is one of the most widely used experimental set-ups to provide a basic understanding of transport mechanisms across junctions with single molecules bonded to metal electrodes. For example, STM-BJ measurements can be used to determine the mechanism for charge transfer(tunneling, resonant transport or sequential hopping) or to understand the nature of charge carriers(electrons or holes) in single molecule junctions. However, these types of single molecule measurements are not limited to advancing the field of molecular electronics – indeed, as we propose here – it can be used to understand fundamentals of charge transfer across bicyclosilanes as building blocks for organic electronic devices. Some pretty interesting findings include:(1) bicyclosilane: both bicyclo[2.2.1]silane and bicyclo[2.2.2]silane have one conductance platform, and the former is larger than the conductance of the latter.(2) extended bicyclosilanes: We found that the molecular conductance decreases exponentially with increasing chain length, which is in agreement with tunneling mechanism. For bicyclo[2.2.2]silane, decay constant β = 0.55 ± 0.14, which is similar to the linear Si chains with a decay constant β = 0.7. In the nanoscale and macro state, electron transport may be very different. Although bicyclo[2.2.2]silane have several conductive paths, it did not bring about the result similar to parallel circuit in the macroscale.