Highly crystalline, continuous parallel arrays of CdSe nanowires have been generated through electrodeposition using photoresist templates. Easy soft imprint nanolithography (ESINL) was used to pattern a commercially available photoresist, Norland Optical Adhesive 60 (NOA 60), deposited onto the ITO substrates, prior to electrodeposition. Using the exposed ITO layer as an electrode, a thin film of CdSe was electrodeposited from an electrolyte containing CdCl2, SeO2, and HCl on the substrate, and the resist was subsequently removed in an alkaline developer solution. The resulting CdSe nanowires were 100 nm in thickness, 300–500 nm in width, and several centimeters in length. Imprinted templates were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and energy-dispersive X-ray spectroscopy (EDX). The SEM analysis confirmed the formation of parallel arrays of nanowires unaffected by the resist lift-off, and the XRD results showed that the CdSe nanowires had a hexagonal structure and that the crystalline structure was unaffected by the photoresist removal.

No abstract

This study intends to design magnetite (Fe3 O4 )-based magnetic fingerprint powders with different particle size distributions. It also investigates the influence of particle size distribution on the visualization of latent fingermarks with as little background staining as possible on the surfaces with various porosities in a systematic way. Two strategies were used to prepare the magnetic fingerprint formulations for this study: milling of coarse magnetite particles for different durations, and mixing of sieved fine particles with different size ranges with coarse particles. Particle size analyses of the prepared magnetic powders, optical microscopy-based roughness analysis of the surfaces and SEM measurements of the visualized fingerprints and representative powders were performed. Mag2 of the formulations prepared through milling and Mag5 and Mag6 of the formulations prepared through sieving and mixing were more successful in the development of latent prints than the rest of the solutions.

Electrodeposition is a key technique to create nanostructures of metals and inorganic semiconductors. Unlike the electrodeposition of metals, the fabrication of nanostructures of binary semiconductors with desired crystallinity and stoichiometry is not straightforward. Herein, we describe the optimization of conditions for the electrodeposition of stoichiometry and crystalline cadmium selenide (CdSe), cadmium telluride (CdTe), and CdSe/CdTe nanostructures. We first identified the optimal conditions for the electrodeposition of CdSe and CdTe with 1:1 stoichiometry by varying the concentrations of Cd 2+ and SeO 2 (or TeO 2 ) and optimizing the electrodeposition potential. We then optimized the pH of the electrolysis solution for increasing the crystallinity of the deposited structures. We then tested the efficacy of our electrodeposition conditions on substrates such as gold, nickel, and indium tin oxide. We used the optimized conditions to electrodeposit semiconductors within anodic aluminum oxide (AAO) membranes to create oriented CdSe and CdTe nanorods, CdSe/CdTe segmented nanorods, and CdSe/CdTe coaxial nanorods. These optimized electrodeposition conditions add a valuable tool in the synthetic toolbox for the synthesis of crystalline semiconductor nanostructures for solar cell applications.

No abstract