Thermally stimulated current (T.S.C.) measurements and their correlation with efficiency and degradation in GaP LED´s

Thermally stimulated current (T.S.C.) measurements have been performed, on p-n junctions in GaP LED´s grown by double liquid phase epitaxy. By studying appropriate junctions, we have been able to observe four deep donors (the energy level of which ranges between 0.27eV and. 0.90eV) on the n-side of the junction and four deep acceptors (the energy level of which ranges between 0.22eV and 0.55eV) on the p-side. A correlation has been established between the presence and concentration of some of these deep states and the quantum efficiency of the corresponding LED in case of pn⁺structure. Increase of the intensity or appearance of the peaks has been observed in the T.S.C. spectrum when the LED´s are degraded by heating under forward bias.