A simple single-source precursor route to the nanostructures of AIN, GaN and InN

In an effort to find a simple and common single-source precursor route for the group 13 metal nitride semiconductor nanostructures, the complexes formed by the trichlorides of Al, Ga and In with urea have been investigated. The complexes, characterized by X-ray crystallography and other techniques, yield the nitrides on thermal decomposition. Single crystalline nanowires of AlN, GaN and InN have been deposited on Si substrates covered with Au islands by using the complexes as precursors. The urea complexes yield single crystalline nanocrystals under solvothermal conditions. The successful synthesis of the nanowires and nanocrystals of these three important nitrides by a simple single-precursor route is noteworthy and the method may indeed be useful in practice.

Coexistence of para and ferromagnetic phases of Fe3+ in undoped CdZnTe (Zn similar to 4%) crystals

The signatures of the coexistence of para and ferromagnetic phases for the Fe3+ charge state of iron have been identified in the low temperature electron spin resonance (ESR) spectra in undoped CdZnTe (Zn similar to 4%) crystals and independently verified by superconducting quantum interference device (SQUID) and AC susceptibility measurements. In the paramagnetic phase the inverse of AC susceptibility follows the Curie-Weiss law. In the ferromagnetic phase the thermal evolution of magnetization follows the well-known Bloch T-3/2 law. This is further supported by the appearance of hysteresis in the SQUID measurements at 2 K below T-c which is expected to lie in between 2 and 2.5 K. (C) 2010 Elsevier Ltd. All rights reserved.