On the Effect of Low-Energy Electron Irradiation in the RF Responsivity of GaN Nanodiodes

Nanodevices are intrinsically strongly influenced by the surrounding environment due to their large surface-to-volume ratio. In this brief, we explore the impact of exposing GaN nanodiodes to a scanning electron microscope (SEM), affecting their dc behavior by reducing the current level, as well as their ac response by modifying the frequency dependence of their voltage responsivity to millimeter waves up to 43.5 GHz. The experiments were performed in a wide range of temperatures from 30 to 300 K. The irreversible changes induced by the low-energy electron irradiation of the SEM beam in the occupation of the traps located at the channel sidewalls, and the accumulation of negative charge within the native oxide filling the trenches, have been found as the responsible of the enhancement of the room temperature responsivity at high frequency and the reduction of the low-frequency dispersion at low temperature.