The apparently contradictory results indicating the ability of DNA to transport charge as well as the possible charge transport mechanisms in DNA have been addressed by making scanning tunneling microscopy (STM) or current-sensing atomic force microscopy measurements using gold nanoparticle (GNP)-DNA complexes bound to a gold substrate designed to minimize nonreproducibility of the specific binding modes and configurations of the DNA-metal contacts. Using these GNP-DNA complexes but a different strand of DNA [13-base-pair poly(dA)-poly(dT) double-stranded DNA] and STM, semiconductorlike charge transport characteristics are demonstrated for DNA; importantly, several different observed I-V characteristics are correlated with different configurations of GNP-DNA complexes as well as with I-V characteristics calculated using a Landauer formalism. These joint measured and simulated I-V characteristics for the GNP-DNA complexes are consistent with charge transport in a semiconductor where the lowest unoccupied molecular orbital energy of the DNA serves as the lowest conduction band energy and the highest occupied molecular orbital energy of the DNA serves as the highest valence band energy.

In designing nanoscale optoelectronic devices based on a small number of active quantum dots, it is of interest to consider that semiconductor nanocrystals (quantum dots) are observed to blink "on" and "off". The time probability distributions scale as an inverse power law for colloidal quantum dots and exponentially for self-assembled dots. Possible mechanisms that cause the inverse power law and exponential blinking statistics are discussed in the paper and the relevance to quantum-dot based system architectures is discussed.

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This paper formulated the interface optical phonon modes for two particular asymmetrical heterostructures: SiC/GaN/Vacuum and AlN/GaN/Vacuum. The interface optical phonon potentials and dispersion relations are determined for these structures. Using these results, the carrier-interfacephonon interaction Hamiltonian is formulated.

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