Low-Frequency Noise in N-GaN with High Electron Mobility

We report on the results of measurements of low frequency noise in n-type gallium nitride (GaN) grown on sapphire with 300 K electron mobility of 790 cm2/V s. The noise spectra have the form of 1/f noise with a Hooge parameter α of approximately 5×10−2. This value of α is two orders of magnitude smaller than that observed before in n-GaN. The obtained results show that the level of flicker noise in GaN, just like that in GaAs and Si, strongly depends on the structural perfection of the material (the amplitude of the 1/f noise is much smaller in material with high mobility). The effects of band-to-band illumination on the low-frequency noise show that 1/f noise in GaN might be caused by the occupancy fluctuations of the tail states near the band edges. This mechanism of the 1/f noise is similar to that in GaAs and Si