Embodiments include systems and methods for producing semiconductor wafers having reduced quantities of point defects. These systems and methods include a tunable ultraviolet (UV) light source, whichis controlled to produce a raster of a UV light beam across a surface of a semiconductor wafer during epitaxial growth to dissociate point defects in the semiconductor wafer. In various embodiments, the tunable UV light source is configured external to a Metal Organic Chemical Vapor Deposition (MOCVD) chamber and controlled such that the UV light beam is directed though a window defined in a wallof the MOCVD chamber.