Summary and Conclusions

and conclusions Thermopower and high electric field transport of a bilayer graphene and graphene nanoribbon are theoretically investigated. Study of thermopower is important from the point of view of applications in thermoelectric devices, power generation, cooling, understanding the electronic structure and the scattering sources. High field transport study is important due to applications in high speed devices, analog and radio-frequency circuits and in understanding various relaxation processes limiting their transport properties. In the introduction chapter, lattice structure and electronic structure of monolayer graphene (MLG), bilayer graphene (BLG) and armchair graphene nanoribbon (AGNR) are given. Moreover, a discussion is given about the relevant scattering mechanisms and the respective matrix elements. A basic general formalism of diffusion thermopower S d and phonon-drag thermopower S g in graphene is developed in Chapter 2. In Chapter 3, diffusion thermopower S d is studied theoretically in bilayer graphene. By employing the Boltzmann transport equation technique an expression for S d is derived. Along with this, mobility μ of the carriers, a complimentary property to S d , is also studied. Sensitivity of S d and μ with respect to the possible scattering due to acoustic phonons (APs), surface polar phonons (SPPs), charged impurity (CI) and short-range disorder (SD) is investigated. S d and μ are presented as functions of temperature T and electron concentration ns for both supported and suspended BLG. In the Bloch-Grüneisen (BG) regime, acoustic phonon limited mobility shows μAP ̴T -4