Module A-4 Molecular Electronics

Bohr Atomic Model

Hydrogen Emission Spectra Principal Quantum Number

Principal Quantum Numbers Orbital Quantum Number l = 0 to l = (n–1)

Quantum Energy States

Principal Quantum Numbers

Molecular Orbital Considerations H  H-H  H-H-H  H-H-H-H (1s electrons) Li  Li-Li  Li-Li-Li  Li-Li-Li-Li (2s electrons) (Li–Li = 2.67 A, H–H = 0.75 A)

Molecular  -Bonding and  * Bonding States

 bonds Electrons in chemical bonds ( e.g. H-H and C-H bonds) are generally quite localized and non-co nducting. These bonds are  bonds.Electrons in chemical bonds ( e.g. H-H and C-H bonds) are generally quite localized and non-co nducting. These bonds are  bonds.

Alkyl Chains and Aliphatic molecular Insulators   type orbits lie in the molecular plane and are insulating

Formulation of Large Molecular Chains

Formation of Energy Bands from Constituent Atoms

Energy Bands for metals, semiconductors and Insulators

Bandgap vs. Chain Length Poly(thiophene)

Saturation Effect All properties approach a saturation value.

Bandgap vs. conjugation length Increased conjugation length  smaller bandgap

Genesis of Nanotechnology 00 Chemistry 96 Chemistry 86 Physics 56 Physics 97 chemistry (Mitre 96)

Single Electron Transistors

Molecular Break junction SET

STM in Molecular Electronic Research Semiconducting