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Highlights: [•] CoFe2O4 films show epitaxial growth despite a large variation in lattice matching with substrates. [•] The relaxed films only show strain under the critical thickness close to the interface when presence. [•] Films are relaxed by epitaxial islands formation and growth defects with increasing thickness. [•] Epitaxial CoFe2O4 shows different growth mechanisms and large variation of magnetic properties. [ABSTRACT FROM AUTHOR]

Abstract: High aspect ratio silicon wire arrays with excellent pattern fidelity over wafer-scale area were grown by chemical vapor deposition at moderate temperature, using a gas mixture of silane and hydrogen chloride. An innovative two-step process was developed for in situ doping of silicon wires by diborane. This process led to high p-type doping levels, up to 1018–1019 cm−3, without degradation of the silicon wire array pattern fidelity. [Copyright &y& Elsevier]

Abstract: Doped SrTiO3 thin films, 55nm thick, were epitaxially grown by Pulsed Laser Deposition with niobium contents ranging from 2 to 5mol% on SrTiO3 and LaAlO3 substrates. The different templates result in different growth defects, film growth mechanism and therefore a different volume fraction of uniformly strained film under the critical thickness. The investigation of the conductivity reveals a significant difference between the two substrate choices, but only at elevated temperatures with conductivity values up to 30% larger for films on SrTiO3 substrates compared with LaAlO3. Whereas in bulk ceramics the niobium level dictates the total conductivity, here it was found that the substrate choice had a greater influence for thin films, in particular at temperatures over 400°C. This finding provides important information on conductive layers in complex heterostructures where strain and defects could work cooperatively. [Copyright &y& Elsevier]

Abstract: We study the growth of silicon nanowires (SiNWs) by chemical vapor deposition (CVD) with aluminum as catalyst. We show that for a growth temperature of 600°C, the silicon precursor partial pressure (SiH4 in this study) is a key parameter for controlling the structural quality of the resulting SiNWs. We find by transmission electron microscopy that at high SiH4 partial pressure, the SiNWs are composed of a monocrystalline core with a high density of surface defects, mainly twins, sheathed by a rough amorphous silicon layer. By contrast, at low SiH4 partial pressure, the SiNWs are monocrystalline with a lower density of surface crystalline defects and a smooth surface. For the low SiH4 partial pressure SiNWs, Al atoms have been detected at the SiNW surface by Auger spectroscopy at level around 3at% and in the SiNW core by energy dispersive X-ray spectroscopy (EDS) at levels around 1at%. Interestingly, higher Al concentrations are measured inside the nano-twin domains by EDS (around ten times increase). Two possible explanations are proposed; stacking faults are induced by Al atoms that lower their energy formation, or Al atoms can be trapped inside these stacking faults due to segregation effect during growth. These findings will be important for growing high quality SiNWs using Al as metal catalyst in reduced-pressure CVD tool. [Copyright &y& Elsevier]