ABSTRACT
Self-assembled nano-arrays have a potential application as solid-phase diagnostics in many biomedical devices. The easiness of its production is directly connected to manufacture cost reduction. In this work, we present self-assembled structures starting from spin coated thin films of carboxylated polystyrene (PSC) and xyloglucan (XG) mixtures on both mica and silicon substrates. AFM images showed PSC nanospheres on top of a homogeneous layer of XG, for both substrates. The average nanosphere diameter fluctuated for a constant speed and it was likely to be independent of the component proportions on the mixture within a range of 30-50% (v/v) PSC. It was also observed that the largest diameters were found at the center of the sample and the smallest at the border. The detected nanospheres were also more numerous at the border. This behavior presents a similarity to spin coated colloidal dispersions. We observed that the average nanosphere diameter on mica substrates was bigger than the nanosphere diameters obtained on top of silicon substrates, under the same conditions. This result seems to be possibly connected to different mixture-surface interactions.
Subject(s)
Aluminum Silicates/chemistry , Glucans/chemistry , Microscopy, Atomic Force/methods , Nanospheres/chemistry , Polystyrenes/chemistry , Silicon/chemistry , Xylans/chemistry , Adsorption , Biomimetic Materials/chemistry , Chloroform/chemistry , Fabaceae/chemistry , Nanotechnology/methods , Particle Size , Seeds/chemistry , Surface PropertiesABSTRACT
We report on vertical architecture hybrid transistor devices using p-type silicon as collector terminal and 2,6-diphenylindenofluorene as organic semiconductor in the emitter layer. Polystyrene spheres were used as shadow masks in order to control the diameter and density of the openings in the Al metallic base. Two processes of sphere deposition were used: electrospray and dip-coating. The electrospray deposition leads to a smaller density of sphere agglomerates, but for the used sphere diameter, approximately 200 nm, the transistor performance is similar for devices prepared with sphere deposition by both techniques. The so constructed permeable-base transistors show common-emitter current gain of the order of 10(2).
