Analysis of charge states in GaN-based nanoribbons using transport and noise studies

GaN-based nanoribbons (NRs) represent important structures because of their unique transport properties. They have high breakdown voltage and can be scaled down to nanosizes. We studied the transport and noise properties of NRs in a wide temperature range applying different external treatments: ultraviolet (UV) excitation and high voltage bias. Characteristic features in the form of bumps were revealed in the temperature dependences of conductivity. The effect becomes more pronounced with decreasing NR width. Such exceptional behavior is related to a contribution of depletion regions at the edges of the NR to the sample conductivity. Characteristic energies of the deep traps in NR structures were obtained using generation-recombination components of measured noise spectra. Noise spectroscopy provides information about dynamic processes in structures. Depletion effects in AlGaN/GaN nanoribbons can be controlled using external UV excitation and applied electric fields. The results are important for understanding confinement effects, including transition to a one-dimensional (1D) transport regime.