Graphene was the first two-dimensional structure obtained experimentally. Its crystalline lattice is a hexagonal network with a unique atom thick, known as "Honeycomb". Cuts in graphene sheets, which favour a certain direction, generate the so-called graphene nanoribbons. Although graphene behaves like a metal, without considering spin polarization or any type of doping, nanoribbons can present metallic, semi-metallic or semiconductor behaviour, depending on the direction of the cutting and/or on the width of the ribbon. In the case of the semiconductor nanoribbons, the width of the band gap can depends directly on the width of the nanoribbon. Generally, the treatment is predominantly computational, for example, the DFT (Density Functional Theory), in order to obtain characteristics such as dispersion curves for nanoribbons, or the treatment can also be experimental. In this work, we first present the diagrams of energy band and the curves of density of states for semiconductor graphene nanoribbons of different widths and in the absence of external influences. Methods of first principles were used to obtain these curves and the method of Green functions of non-equilibrium was used to obtain the electronic transport. Subsequently, we investigated the influence of the hydrogenation, of the temperature and of the mechanical stress over the system, in order to analyse the behaviour of the electronic transport with and without external influences. It is noteworthy that the graphene nanoribbons present real possibilities of application in nanoelectronic devices, such as nanodiodos and nanotransistores. For this reason, it is important to understand how external factors affect the properties of such materials. So, it is expected that the properties of electronic devices are also influenced in the same way as the properties of the nanoribbons are influenced too.
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