The performance of thin film metal-insulator-metal (MIM) diodes is investigated for a variety of large and small electron affinity insulators using ultrasmooth amorphous metal as the bottom electrode. Nb2O5, Ta2 O5, ZrO2, HfO2, Al2 O3, and SiO2 amorphous insulators are deposited via atomic layer deposition (ALD). Reflection electron energy loss...