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Atom probe tomography allows for three-dimensional reconstruction of the elemental distribution in materials at the nanoscale. However, the measurement of the chemical composition of compound semiconductors may exhibit strong biases depending on the experimental parameters used. This article reports on a systematic analysis of the composition measurement of III–N binary (AlN, GaN) and ternary compounds (InGaN, InAlN), MgO, and ZnO by laser-assisted tomographic atom probe as a function of laser power and applied DC bias. We performed separate series of measurements at constant bias, constant laser pulse energy, and constant detection rate and a spatial analysis of the surface field through detector hitmap ratios of elemental charge states. As a result, (i) we can determine the separate roles of laser energy and surface fieldthe latter being the dominant factor under standard conditions of analysis; (ii) we compare the behavior of different samples and (iii) different materials; and (iv) we critically discuss the reliability of the measurement of InxGa1–xN and InxAl1–xN alloy fractions and of the Tb concentration in rare-earth-doped ZnO.

The field-emission properties of SnO2:WO2.72hierarchical nanowire heterostructure have been investigated. Nanoheterostructure consisting of SnO2nanowires as stem and WO2.72nanothorns as branches are synthesized in two steps by physical vapor deposition technique. Their field emission properties were recorded. A low turn-on field of ∼0.82 V/μm (to draw an emission current density ∼10 μA/cm2) is achieved along with stable emission for 4 h duration. The emission characteristic shows the SnO2:WO2.72nanoheterostructures are extremely suitable for field-emission applications.

Here, we report the synthesis of vertically aligned gallium sulfide (GaS) nanohorn arrays using simple vapor–liquid–solid (VLS) method. The morphologies of GaS nano and microstructures are tuned by controlling the temperature and position of the substrate with respect to the source material. A plausible mechanism for the controlled growth has been proposed. It is important to note that the turn-on field value of GaS nanohorns array is found to be the low turn-on field 4.2 V/μm having current density of 0.1 μA/cm2. The striking feature of the field emission behavior of the GaS nanohorn arrays is that the average emission current remains nearly constant over long time without any degradation.