MgZnO Nanocrystals: Mechanism for Dopant-Stimulated Self-Assembly

Understanding the growth behavior of nanocrystals (NCs), especially when heteroatoms are introduced, is very important for the optimization of doping (or alloying) and optoelectronic performances. Here, it is reported on the observation of alloying-facilitated self-assembly of MgZnO NCs and the underlying mechanism of alloying concentration-dependent surface grafting. Using the developed one-pot thermolysis of Zn and Mg organic salts with the help of oleylamine (OAm) and oleic acid (OA), the Mg ions can be introduced into the ZnO lattice without phase separation with concentrations as high as 20%. Interestingly, with the increase of Mg alloying concentration, the morphologies of the products transform from monodispersed NCs to nanoflowers, and then nanobouquet superstructures, which have quasi-monocrystal features and obey the oriented attachment rules. According to the analyses of surface functional groups, a mechanism involving concentration-dependent surface grafting is proposed for such alloying-facilitated self-assembly.

Heterogeneous phase formation in diluted magnetic semiconducting Zn1−x−yCoxAlyO (CAZO) nanoparticles

This article reports a systematic investigation of the synthesis and structural characterization of composite CAZO [(Zn_1−x−yCo_xAl_yO; x = 0.04, 0.03, 0.02; y = 0.01, 0.02, 0.03)] nanoparticles from combustion.

Fabrication and sensing behavior of one-dimensional ZnO-Zn2GeO4 heterostructures

Well-crystalline one-dimensional ZnO-Zn2GeO4 (ZGO) heterostructures were successfully synthesized using a high-temperature solid-state reaction between the ZnO and Ge layers of ZnO-Ge core-shell nanostructures. The polycrystalline ZGO crystallites had a thickness in the range of 17 to 26 nm. The high-temperature solid-state reaction induced grooves and crystal defects on the surfaces of the ZGO crystallites. The sensors made from the ZnO-ZGO heterostructures exhibited a marked photocurrent response to UV light at room temperature and a gas sensing response to acetone gas at 325°C. The observed sensing properties are attributed to the rugged surface of the ZGO heterointerfaces between ZnO and ZGO, surface crystal defects of ZGO, and cross-linked contact regions of ZnO-ZGO.