Structural and magnetic properties in Mn-doped GaN grown by metal organic chemical vapor deposition Appl. Phys. Lett. 92, 152116 (2008); 10.1063/1.2909545 Anomalous magnetic properties of the ferrimagnetic semiconductor on Ga-doped sulphur spinel

Structural and magnetic properties of (Ga,Mn)N layers grown on SiC by reactive molecular beam epitaxy

GaAs layers grown by molecular beam epitaxy (MBE) at substrate temperatures between 200 and 300 °C were studied using transmission electron microscopy (TEM), x-ray diffraction, and electron paramagnetic resonance (EPR) techniques. High-resolution TEM cross-sectional images showed a high degree of crystalline perfection of these layers. For a layer grown at 200 °C and unannealed, x-ray diffraction revealed a 0.1% increase in the lattice parameter in comparison with bulk GaAs. For the same layer, EPR detected arsenic antisite defects with a concentration as high as 5×1018 cm−3. This is the first observation of antisite defects in MBE-grown GaAs. These results are related to off-stoichiometric, strongly As-rich growth, possible only at such low temperatures. These findings are of relevance to the specific electrical properties of low-temperature MBE-grown GaAs layers.

Articles you may be interested inAbove room-temperature ferromagnetism of Mn delta-doped GaN nanorods Appl. Phys. Lett.Ferromagnetic behavior of GaN doped with Mn (Ga 1Ϫz Mn z N) grown by the ammonothermal and chemical transport methods is discussed in terms of a second phase ͑ferromagnetic one͒ produced during the growth process. The reference manganese nitride samples grown by the same method as ͑Ga,Mn͒N reveal room-temperature ferromagnetic behavior, depending on the growth details. Different Mn x N y phases are suggested to be responsible for ferromagnetic behavior of ͑Ga,Mn͒N.

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It is shown that ammonothermal method can be successfully used to synthesize GaN powder of good crystallographic quality from ammonia solution at high pressure and a moderate temperature. The size of obtained GaN powder grains was of a few micrometers. The improvement of the powder crystalline quality (examined by X-ray rocking curve, scanning electroii microscopy and luminescence measurements) with increasing molar proportion of mineralizer was observed. It was therefore possible to conclude that high molar proportion of mineralizer in ammonia solution plays a crucial role in the polycrystal growth process. Visible luminescence of high efficiency from the GaN powder was found.

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