We have investigated the mechanisms of photoelectron tunneling into gold from tipless, nitridized, gallium arsenide microcantilevers through thin polymers. A study of the tunnel bias, tunnel distance, and light excitation power dependence of the tunneling photo-current reveals the tunneling process to be Fowler-Nordheim like. Both the value of the dielectric constant and the sign of the tunneling photocurrent at low excitation power suggest the important role of polymer defects.