Correlation of a generation-recombination center with a deep level trap in GaN

Abstract

We report on the identification of a deep level trap centre which contributes to generation-recombination noise. A n-GaN epilayer, grown by MOCVD on sapphire, was measured by deep level transient spectroscopy (DLTS) and noise spectroscopy. DLTS found 3 well documented deep levels at E[subscript c] − 0.26 eV, E[subscript c] − 0.59 eV, and E[subscript c] − 0.71 eV. The noise spectroscopy identified a generation recombination centre at E[subscript c] − 0.65 ± 0.1 eV with a recombination lifetime of 65 μs at 300 K. This level is considered to be the same as the one at E[subscript c] − 0.59 eV measured from DLTS, as they have similar trap densities and capture cross section. This result shows that some deep levels contribute to noise generation in GaN materials.