SE ESTUDIA LA CINÉTICA DE LOS PROCESOS ULTRARRÁPIDOS QUE LLEVAN A LA CONDICIÓN DE TERMALIZACIÓN DE UN PLASMA FOTOEXCITADO EN SISTEMAS SEMICONDUCTORES. ANALIZAMOS LA EVOLUCIÓN TEMPORAL DE UNA POBLACIÓN GENERADA POR UN PULSO ÓPTICO FINITO, DESDE EL COMIENZO DEL PULSO HASTA EL TIEMPO EN EL QUE LA POBLACIÓN ALCANZA UNA CONDICIÓN DE CUASI EQUILIBRIO. CALCULAMOS LOS FLUJOS DE ENERGÍA CAUSADOS POR LOS MECANISMOS PRINCIPALES DE INTERACCIÓN A LO LARGO DE LAS DIFERENTES ETAPAS POR LAS QUE PASA EL SISTEMA. HACEMOS NUESTRO ANÁLISIS USANDO UN CONJUNTO NO LINEAL DE ECUACIONES DE RAZÓN DE CAMBIO QUE GOBIERNAN LA EVOLUCIÓN TEMPORAL DE LA POBLACIÓN DE PORTADORES EN EL ESPACIO DE ENERGÍAS. CONSIDERAMOS LOS MECANISMOS PRINCIPALES DE INTERACCIÓN, INCLUYENDO EL APANTALLAMIENTO DINÁMICO Y LOS EFECTOS DE POBLACIÓN DE FONONES.AbstractTHE KINETICS OF ULTRA-FAST PROCESSES WHICH LEADS TO THE THERMALIZATION CONDITION OF A PHOTO-EXCITED PLASMA IN SEMICONDUCTOR SYSTEMS IS STUDIED THEORETICALLY. WE ANALYZE THE TIME EVOLUTION OF A CARRIER POPULATION GENERATED BY A FINITE OPTICAL PULSE, FROM THE BEGINNING OF THE PULSE UNTIL THE TIME IN WHICH THE CARRIER POPULATION REACHES A QUASI-EQUILIBRIUM CONDITION. WE CALCULATE THE ENERGY FLUXES CAUSED BY THE MAIN INTERACTION MECHANISMS ALONG THE DIFFERENT STAGES THE SYSTEM PASSES THROUGH. OUR ANALYSIS IS DONE BY USING A SET OF NON-LINEAR RATE EQUATIONS WHICH GOVERN THE TIME EVOLUTION OF THE CARRIER POPULATION IN THE ENERGY SPACE. WE CONSIDER THE MAIN INTERACTION MECHANISMS, INCLUDING DYNAMIC SCREENING AND PHONON POPULATION EFFECTS.THE KINETICS OF ULTRA-FAST PROCESSES WHICH LEADS TO THE THERMALIZATION CONDITION OF A PHOTO-EXCITED PLASMA IN SEMICONDUCTOR SYSTEMS IS STUDIED THEORETICALLY. WE ANALYZE THE TIME EVOLUTION OF A CARRIER POPULATION GENERATED BY A FINITE OPTICAL PULSE, FROM THE BEGINNING OF THE PULSE UNTIL THE TIME IN WHICH THE CARRIER POPULATION REACHES A QUASI-EQUILIBRIUM CONDITION. WE CALCULATE THE ENERGY FLUXES CAUSED BY THE MAIN INTERACTION MECHANISMS ALONG THE DIFFERENT STAGES THE SYSTEM PASSES THROUGH. OUR ANALYSIS IS DONE BY USING A SET OF NON-LINEAR RATE EQUATIONS WHICH GOVERN THE TIME EVOLUTION OF THE CARRIER POPULATION IN THE ENERGY SPACE. WE CONSIDER THE MAIN INTERACTION MECHANISMS, INCLUDING DYNAMIC SCREENING AND PHONON POPULATION EFFECTS.