Optoelectronic Properties of Density-Controlled ZnO Nanopillar Arrays

Abstract

An effective method of controlling the density of ZnO nanopillars (ZnO-NPs) by using the self-assembled silver nanoislands as the growth catalyst is demonstrated. We were able to vary the density of the ZnO-NPs to within the range of ∼10–30 μm–2 by properly manipulating the size distribution of the silver nanoislands partially covering the Si substrates. Continuous silver film can also be used as the catalyst to facilitate the growth of ZnO islands and pillars on Si substrates, albeit with much less control of the resultant density and morphological appearances. The field-emission measurements indicate that the performance of field emission for ZnO-NPs can be improved markedly by reducing the density of the ZnO-NPs. The turn-on field of the low-density ZnO-NPs was as low as 2.39 V/μm with a corresponding current density of 10 μA/cm2 and a field enhancement factor (β value) of ∼3500. The enhancement of field-emission characteristics is attributed to the much reduced field screen effect by properly controlled density of the ZnO-NPs.

Exploring Low Internal Reorganization Energies for Silicene Nanoclusters

“…It is observed that small H-SiNCs have low electron affinity and high electron reorganization energy. On the contrary, large H-SiNCs have high electron affinity and low electron reorganization energy, two important factors for good n-type materials [33]. In the case of linear or nearly linear H-SiNCs, Fig.…”

“…The same procedure was carried out for the cation state. Thus, the hole reorganization energy is given by [33]…”

A highly selective and sensitive benzothiazole‐based ‘turn‐on’ fluorescent sensor for Hg2+ ion

“…These results demonstrated that other competing metal ions did not interfere with the binding of Hg 2+ with TDA and could not disrupt the highly fluorogenic detection of TDA for Hg 2+ . Therefore, it is not necessary to use any masking reagent, whereas some sensing systems require masking agent [31,32] to eliminate metal ion interference in the determination of Hg 2+ .…”

Sensitive and Selective Gold Nanomaterials Based Optical Probes

“…When organic fluorophores such as rhodamine B are used, 13-and 32-nm Au NPs are ideal quenchers due to their high quenching efficiency and stability. 26 DNAfunctionalized Au NPs and a DNA binding dye such as OliGreen (OG) have been used for the detection of Hg 2+ ions. 67 The fluorescence of OG is weak when it interacts with the DNA on the Au NP surface, mainly because SET occurs.…”

“…24,25 Through specific interaction of Au atoms/ions with metal ions, citrate-Au NPs were used for the detection of Hg 2+ . 26 However, citrate-Au NPs do not provide selectivity for other analytes. In addition, citrate-Au NPs are not stable in harsh conditions (high and low pH values and high salt), leading to loss in selectivity, sensitivity, and reproducibility.…”