Optical characterization of the "E2" deep level in GaN

The correspondence between the E2 level (similar to E-c-0.55 eV) in n-type GaN undergoing thermoionization and photoionization was established. The op tical cross section in the vicinity of the threshold for photoionization of this level was measured by means of capacitance transient spectroscopy. An alysis using the formulation of Chantre yielded the optical activation ener gy, E-0=0.85 eV, and the Franck-Condon parameter, d(FC)=0.30 eV at 90 K. (C ) 1999 American Institute of Physics. [S0003-6951(99)03004-1].