LaAlO3 is grown on SrO terminated (100) SrTiO3, and (110) SrTiO3, producing insulating heterointerfaces without light. Photocurrent spectroscopy at low temperatures reveals a broad distribution of interface states between 2 eV and 2.7 eV at both interfaces, with a higher density in the (110) case concomitant with relatively shallow traps. The photocurrent relaxation can be well fitted by a stretched exponential form, confirming energetically distributed electron traps. Photo-carrier lifetimes are larger than a few hundred seconds for optical excitation approaching the SrTiO3 band-gap energy, providing the opportunity to study transient light-induced properties at low temperatures. Show Partial Abstract