[en] The diffraction behaviour of stacked layers of graphene and hexagonal boron nitride are studied computationally by direct calculation of the diffraction pattern using the Debye scattering equation. Analysis of the position and profile of the diffraction peaks show that while single-layer graphene is unambiguously a 2D material, ordered stacks of three or more layers diffract as bulk material. Following the Scherrer equation, we correlate the known crystallite size with the diffraction peak parameters and observe strong affine relationships which exist separately for single-layer, bi-layer and three or more layer (bulk) structures. We determine a series of expressions to calculate the crystallite size which do not suffer the well-known size-dependence or rely on assumptions about the shape. We present a detailed workflow showing how these expressions can be applied to experimental data. (paper)

[en] Mixed-mode deposition of carbon is an extension of high-power impulse magnetron sputtering in which a short-lived arc is deliberately allowed to ignite on the target surface to increase the ionised fraction of carbon in the deposition flux. Here we investigate the ignition and evolution of these arcs and examine their behaviour for different conditions of argon pressure, power supply voltage, and current. We find that mixed-mode deposition is sensitive to the condition of the target surface, and changing the operating parameters causes changes in the target surface condition which themselves affect the discharge in a process of negative feedback. Initially the arcs are evenly distributed on the target racetrack, but after a long period of operation the mode of erosion changes and arcs become localised in a small region, resulting in a pronounced nodular structure. We also quantify macroparticle generation and observe a power-law size distribution typical of arc discharges. Fewer particles are generated for operation at lower Ar pressure when the arc spot velocity is higher. (paper)