Deep Levels in GaN p-n Junctions Studied by Deep Level Transient Spectroscopy and Laplace Transform Deep-Level Spectroscopy

p(+)-n GaN diodes were studied by means of conventional deep level transient spectroscopy and Laplace transform deep-level spectroscopy methods within the temperature range of 77-350 K. Deep level transient signal spectra revealed the presence of a majority and minority trap of indistinguishable signatures. The Laplace transform deep-level spectroscopy technique due to its superior resolution allows us to unambiguously identify and characterize the traps. The apparent activation energy and capture cross-section for the majority trap were found to be equal to 0.63 eV and 2 x 10(-16) cm(2) and for the minority trap 0.66 eV and 1.6 x 10(-15) cm(2). It has been confirmed that the Laplace transform deep-level spectroscopy technique is a powerful tool in characterization of the traps of close signatures.