Hyperdoped Si formed by implantation followed by pulsed laser melting is a promising material for enhanced near-infrared photodetection. To realize the full potential of this material, it is crucial to understand the nature of defects arising from the fabrication process and how these may impact device operation. Here, we identify through deep level transient spectroscopy the presence of a range of defects in the substrate depletion layer that arise from interactions between high dose ion implantation and pulsed laser melting, and investigate their annealing behavior up to 650 degrees C. In particular, the detection of a vacancy complex E-1(0.35) with densities as high as 10(14) cm(-3) indicates that optical transitions between this level and the valence band may compete with the Au donor center, and hence could potentially contribute to the photocurrent in hyperdoped photodiodes. Published under license by AIP Publishing.