[en] With traditional semiconductor technology approaching the limits of scaling and chip integration, the discovery of graphene and its astonishing properties stood as a promising alternative for future electronics. In order to adequately put into context the possibilities of graphene, it is critical to investigate the microscopic properties of electronic transport in this material. With this objective, a Monte Carlo simulator for graphene that includes the dynamics of electrons and holes, with especial focus on hot carrier phenomena, like hot phonons, Auger processes, and phonon-assisted generation and recombination mechanisms has been developed. The analysis of electronic transport at high fields allowed to quantify the relative impact that self heating and hot phonons have in the steady state drift velocity of the carriers and temperature. Linear sheet current behavior at high fields was found to be the result of free charge carriers created through impact ionization collisions. Velocity fluctuation phenomena in graphene were studied employing various numerical methods aimed at the analysis of specific transient dynamics (under the application of switching or AC electric fields). The frequency-dependent noise temperature was obtained from the diffusivity an differential mobility, and the feasibility of generating high-order harmonics in graphene, was presented in terms of the detection bandwidth. The potential of graphene for optoelectronic applications requires also a deep understanding of the ultrafast relaxation processes that carriers undergo after being exposed to light with an adequate wavelength. A thorough exploration of this process, with particular focus on the initial photoexcitation conditions, the effect of out-of-equilibrium phonons and the influence of an underlying substrate is presented, together with an experimental pump and probe differential transmission spectroscopy approach. An initial version of a simulator of 2D material-based devices is presented, which allows to set the basis for future research in the field of Monte Carlo modeling of this kind of electronic devices.

[es] Con los l?mites tecnol?gicos de las tecnolog?as de semiconductores tradicionales alcanzando los l?mites de escalado y integraci?n en chip, el descubrimiento del grafeno y sus impresionantes propiedades supuso una prometedora alternativa para el futuro de la electr?nica. Para contextualizar adecuadamente las posibilidades del grafeno, la investigaci?n de las propiedades micrsoc?picas del transporte electr?nico es una tarea crucial. Con este objetivo, se ha desarrollado un simulador Monte Carlo para grafeno, que incluye la din?mica de electrones y huecos, con espacial atenci?n a fen?menos de portadores calientes, como fonones fuera de equilibrio, procesos Auger o generaci?n/recombinaci?n asistida por fonones. El an?lisis del transporte electr?nico a campos altos permiti? cuantificar el impacto relativo del autocalentamiento y los fonones calientes sobre la velocidad de deriva en condiciones estacionarias y la temperatura del material. Adem?s se observ? un comportamiento lineal de la corriente debida a la ionizaci?n por impacto. Se ha estudiado la fenomenolog?a relacionada con fluctuaciones empleando diversos m?todos num?ricos orientados a condiciones transitorias particulares (saltos abruptos de campo o se?ales AC). La temperatura del ruido dependiente de la frecuencia se obtuvo a partir de la difusividad y movilidad diferencial los portadores, y la viabilidad de la generaci?n de arm?nicos de orden alto en grafeno se presenta en t?rminos del ancho de banda l?mite para su detecci?n. El potencial del grafeno para aplicaciones optoelectr?nicas precisa de una comprensi?n detallada de los procesos de relajaci?n ultrarr?pida que sufren los portadores fotoexcitados con longitudes de onda apropiadas. Llevamos a cabo un examen exhaustivo de este proceso, con especial atenci?n a las condiciones iniciales de fotoexcitaci?n, el papel de los fonones calientes, y el efecto del sustrato. Finalmente presentamos una versi?n inicial de simulador para dispositivos electr?nicos basados en materiales 2D, que cimentar? las l?neas futuras de investigaci?n en el campo del modelado Monte Carlo de estos dispositivos.