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Fabrication of graphene devices is often hindered by incompatibility between the silicon technology and the methods of graphene growth. Exfoliation from graphite yields excellent films but is good mainly for research. Graphene grown on metal has a technological potential but requires mechanical transfer. Growth by SiC decomposition requires a temperature budget exceeding the technological limits. These issues could be circumvented by growing graphene directly on insulator, implying Van der Waals growth. During growth, the insulator acts as a support defining the growth plane. In the device, it insulates graphene from the Si substrate. We demonstrate planar growth of graphene on mica surface. This was achieved by molecular beam deposition above 600°C. High resolution Raman scans illustrate the effect of growth parameters and substrate topography on the film perfection. Ab initio calculations suggest a growth model. Data analysis highlights the competition between nucleation at surface steps and flat surface. As a proof of concept, we show the evidence of electric field effect in a transistor with a directly grown channel.

Thin layers of SrHfO3, BaHfO3 and BaZrO3 are deposited onto TiN substrates and investigated in view of memory capacitor applications. The as deposited layers are amorphous and show dielectric constants of about 20. Rapid thermal annealing induces crystallization in the cubic perovskite phase and results in an increase of the dielectric constant up to 45. A combination of X-ray absorption spectroscopy (XAS) and photoemission spectroscopy measurements reports high electronic band gap values comparable with that of reference HfO2 layers.