Influence of buffer layers on Ni thin film structure and graphene growth by CVD

• Published in: Journal of physics. D, Applied physics Applied physics, 2015-11, Vol.48 (45), p.455302-455311
• Main Authors: Ozceri, Elif, Selamet, Yusuf
• Format: Article
• Language: English
• Subjects: Adhesives; Aluminum oxide; buffered growth; Buffers; CVD; Dewetting; film pretreatment; Graphene; graphene growth; Nickel; Surface roughness; thin film dewetting; Thin films
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/48/45/455302

Buffer and/or adhesive layers were used to decrease the dewetting of Ni thin film at graphene growth temperatures of around 900 °C. Depositing a thin buffer (Al2O3) layer onto SiO2/Si substrate significantly reduced the dewetting effect and surface roughness of Ni catalyst film. Thin adhesive (Cr) layers with or without Al2O3 buffer layers increased the texturing in (1 1 1) orientation, which was promoted by growing at an elevated temperature (450 °C). The effects of pretreatment and growth temperature on crystal orientation, grain size and surface roughness of Ni film were analyzed. Our results indicated a large positive correlation coefficient between the film thickness and surface roughness for thinner and non-buffered films, and a negative correlation coefficient between the thickness and 900 °C -annealed film roughness for thicker and buffered films. The graphene coverage was greatly improved over the films grown with Al2O3 and/or Cr layers. In summary, we suggest that growing high quality, large area, 1- or 2-layer graphene on polycrystalline Ni transition metal thin film is optimized by using Al2O3 and/or Cr layers to reduce Ni dewetting, surface roughness, and groove depth while controlling grain size and texturing in (1 1 1) orientation by annealing at 900 °C.