A method is provided for producing crystalline nanoparticle semiconductor material. The method includes the steps of mixing a precursor in a solvent to form a reaction mixture and subjecting the reaction mixture to microwave dielectric heating at sufficient power to achieve a superheating temperature of the reaction mixture. A growth-phase reaction is permitted to proceed, wherein nanoparticles are formed in the heated reaction mixture. The reaction is then quenched to substantially terminate nanoparticle formation.