Deep levels and processes in the course of degradation of GaP:N LED's

Degradation of GaP:N LED's at temperatures of 373, 423, and 473 K and at current stresses of 2.6 and 26 A cm−2 is measured. The changes induced by the degradation are monitored by deep level transient spectroscopy (DLTS) measurement, radiative power, and C–U characteristics. Thirteen deep levels are found and five from them are responsible for the degradation. The concentration profiles of shallow donors and one deep level (nitrogen-related electron trap at 0.45 eV) are measured, too; they are the same as the previously proposed concentration profiles for these two levels. The activation energies for the creation of two deep levels causing the degradation are determined. The processes in the course of the degradation are described in terms of the results obtained.