Mazher, Javed (Professor)Telay, Berhanu2018-07-122023-11-182018-07-122023-11-182012-06http://etd.aau.edu.et/handle/12345678/8241We have investigated the phenomenal of half-metallicity among various novel conformations of graphene nanoribbons (GNRs). The Density of States (DOS) and the Transmission spectrum (TS) of zigzag GNRs doped with boron (B), Nitrogen (N) and Oxygen (O) atoms and undoped but with vacancies are independently investigated by first-principle calculations. A new scheme of spin diode architecture is identified to achieve half-metallicity in ZGNRs by doping B atoms at one edge and N atoms at the other as well as B atom at one edge and O atom at the other edge. We found that the origin of the nearly half-metallic state is due to interactions between the edge states and B-N or B-O atoms which provide direct control over the electron occupation of the edge states by inducing large chemical potential difference between the edge states. We have also found that the ZGNR spintronicity is vacancy concentration dependent. Particularly, for single vacancy site the FM coupling among the zigzag edges are more favorable, while double vacancy sites are found to promote the AFM edge coupling. The as mentioned results of the nearly half-metallicity are presented in the thesis by corroborating them with the results of spin polarization. The prospects of nearly half metallic results are also discussed in context to mangetoresistive device performance.enHalf-Metallicity AmongThesis