Quantifying atom-scale dopant movement and electrical activation in Si:P monolayers.

Advanced hydrogen lithography techniques and low-temperature epitaxial overgrowth enable the patterning of highly phosphorus-doped silicon (Si:P) monolayers (ML) with atomic precision. This approach to device fabrication has made Si:P monolayer systems a testbed for multiqubit quantum computing architectures and atomically precise 2-D superlattice designs whose behaviors are directly tied to the deterministic placement of single dopants. However, dopant segregation, diffusion, surface roughening, and defect formation during the encapsulation overgrowth introduce large uncertainties to the exact dopant placement and activation ratio.

AC signal characterization for optimization of a CMOS single-electron pump.

Pumping single electrons at a set rate is being widely pursued as an electrical current standard. Semiconductor charge pumps have been pursued in a variety of modes, including single gate ratchet, a variety of 2-gate ratchet pumps, and 2-gate turnstiles. Whether pumping with one or two AC signals, lower error rates can result from better knowledge of the properties of the AC signal at the device.

Biofunctionalization of PEDOT films with laminin-derived peptides.

Unlabelled: Poly(3,4-ethylenedioxythiophenes) (PEDOT) have been extensively explored as materials for biomedical implants such as biosensors, tissue engineering scaffolds and microelectronic devices. Considerable effort has been made to incorporate biologically active molecules into the conducting polymer films in order to improve their long term performance at the soft tissue interface of devices, and the development of functionalized conducting polymers that can be modified with biomolecules would offer important options for device improvement. Here we report surface modification, via straightforward protocols, of carboxylic-acid-functional PEDOT copolymer films with the nonapeptide, CDPGYIGSR, derived from the basement membrane protein laminin.

Study of the nanoscale morphology of polythiophene fibrils and a fullerene derivative.

Nanoscale blending of electron-donor and electron-acceptor materials in solution-processed bulk heterojunction organic photovoltaic devices is crucial for achieving high power conversion efficiency. We used a classic blend of poly(3-hexylthiophene)/phenyl-C61-butyric acid methyl ester (P3HT/PCBM) as a model to observe the nanoscale morphology of the P3HT fibrils and PCBM nanoclusters in the mixture. Energy-filtered transmission electron microscopy (EFTEM) clearly revealed a nanoscopic phase separation.

The temporal pattern of captan residues on apple leaves and fruit under field conditions in relation to weather and canopy structure.

Background: Captan is an important fungicide for controlling diseases in horticultural crops. Understanding its dissipation is important for estimating dietary risks and optimising pesticide application. Field experiments were conducted on apple leaves and fruit to investigate (1) the temporal variability of captan residues, (2) the contribution of several factors to the variability in residues and (3) the relationship between residues and climatic conditions.

The effects of temperature, humidity and rainfall on captan decline on apple leaves and fruit in controlled environment conditions.

Background: Captan is an important fungicide for controlling diseases in horticultural crops. Predicting its dissipation is important for estimating dietary risks and optimising pesticide application. Experiments were conducted to determine the relationship of captan loss on apple leaves with temperature, humidity and rainfall, and to investigate captan loss on fruit in dry conditions.