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Abstract: The plasma treatment of rapid heating was introduced for increasing fracture strength of free-standing diamond films. The effects of plasma high temperature annealing treatment on surface morphology, internal stress, vacancy defects, impurities and fracture strength of free-standing diamond films were investigated by scanning electron microscopy (SEM), Raman, positron annihilation technique (PAT) and mechanical property testing. It showed that the fracture strength of the diamond films increases up to 70% for lower fracture diamond films with treating temperature (1500–1600°C). The graphitization in surface and interior of diamond films would be produced by high temperature treatment more than 1700°C. Fracture strengths of diamond films could be enhanced after high temperature treatment and the main factor of that was compressive stress state in diamond films induced by graphitization. The impurity of N was segregated and integrated with vacancy cluster to become [N–V]0 and [N–V]−. [Copyright &y& Elsevier]

Abstract: Highly c-axis oriented ZnO film is often deposited on diamond substrates by RF magnetron sputtering and widely used for high frequency surface acoustic wave (SAW) devices. Deposition temperature is a key factor affecting the quality of the ZnO film. Different quality polished free-standing diamond films prepared by DC Arc Plasma Jet were used as the substrates to deposit ZnO films at different temperatures. Effect of the deposition temperature and the quality of the diamond films on the properties of the ZnO films were investigated by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that highly c-axis oriented ZnO films can be much easier deposited on the optical-grade diamond films with <111> preferred orientation than the tool-grade diamond films with <220> preferred orientation. The optimal deposition temperature is 200°C for highly c-axis oriented and lower roughness ZnO films. Acoustic phase velocity of more than 10,000m/s for the SAW devices based on the ZnO/optical-grade free-standing diamond films was obtained. [Copyright &y& Elsevier]

Abstract: A destroyable Ti interlayer on graphite substrate was used for fabrication of crack-free free-standing diamond films by high-power DC Arc Plasma Jet. Ti interlayer was arc ion plated on the polycrystalline graphite substrate. The thickness, morphology and composite phase of the Ti interlayer were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Titanium carbide (TiC) was detected in both sides of the interlayer, which played an important role with respect to reasonable adhesion and diamond nucleation. Semi-translucent and crack-free diamond films were obtained and characterized by SEM and Raman spectroscopy. It is shown that the diamond films so obtained have excellent Raman signature. The overall results suggest that plating Ti interlayer on graphite substrate is an effective way to obtain potentially crack-free free-standing diamond films. [Copyright &y& Elsevier]