Galvanomagnetic measurements in graphene samples

Grafen is a material attracting considerable attention due to its excellent features. One of the greatest features of graphene is its electronic characteristic that makes it promising metarial for electronic devices. In this thesis study, galvanomagnetic measurements have been performend in Chemical-Vapour-deposited single-layer graphene on TiO2/Si substrate (SLG/TiO2/Si) that is supplied by Bilkent University. Low field Hall effect measurements on Hall-bar shaped SLG/TiO2/Si sample have been made in the temperature range between 1,8-269,5 K as a function of temperature. Scattering mechanisms which affect characteristics of electronic transport was investigated by numerical calculation fitting to experimental data for temperature dependence of Hall mobility (μ_H). This process has been done for single layer graphene growth epitaxial on SiC substrate and single layer graphene growth by CVD on SiO2/Si substrate. İonized impurity scattering, longitual acoustic fonon scattering and remote interfacial optical fonon scatterings were used for numerical calculations. Shubnikov de Hass measurements have been performed in temperature range between 1,8 K and 269,5 K and magnetic fields up to 11 T. 2D carrier density and Fermi enerji levels have been determined by periods of oscillations obtained by two different technics. Other transport parameters of sample like effective mass (m^*), quantum lifetime (τ_q) obtained from temperature and magnetic field dependence of SdH oscillation amplitude. Values of transport lifetime to quantum lifetime ratio (τ_t⁄τ_q ), Hall density (N_H), Hall mobility (μ_H) of samples which have different substrate have been compared and investigated affects of these parameters on transport phenomena.