Thermally-Enhanced Quantum Efficiency of a Hot Electron Laser Assisted Cathode

We experimentally investigated the impact on electron emission of adding thermal energy to a Hot Electron Laser Assisted Cathode (HELAC). We observed an increase in photo-gated emission with temperature up to a certain point where the photo-gated emission mechanism was destroyed due to insulator breakdown in the device. We observed that this breakdown is imminent after a sudden increase in device current. We hypothesize this results from ohmic heating thermal runaway in the insulator, permanently damaging the device's response to absorbed photons. We aim to more precisely predict and avoid this breakdown, while operating the HELAC in a temperature range where sustainable improvement in quantum efficiency is feasible.