  We studied electric current and noise in planar GaN nanowires (NWs). The
results obtained at low voltages provide us with estimates of the depletion
effects in the NWs. For larger voltages, we observed the space-charge limited
current (SCLC) effect. The onset of the effect clearly correlates with the NW
width. For narrow NWs the mature SCLC regime was achieved. This effect has
great impact on fluctuation characteristics of studied NWs. At low voltages, we
found that the normalized noise level increases with decreasing NW width. In
the SCLC regime, a further increase in the normalized noise intensity (up to
1E4 times) was observed, as well as a change in the shape of the spectra with a
tendency towards slope -3/2. We suggest that the features of the electric
current and noise found in the NWs are of a general character and will have an
impact on the development of NW-based devices.
