Degradation mechanisms in high power InGaN semiconductor lasers investigated by electrical, optical, spectral and C-DLTS measurements

摘要

The aim of this work is to study the degradation processes in high power InGaN semiconductor lasers, by means of electrical, optical, spectral and capacitance deep-level transient spectroscopy measurements. The devices were submitted to two different stress experiments, (i) a constant current stress at 1.5 A and 45 degrees C, and (ii) a temperature/bias step stress at 1 A and increasing temperature. Results demonstrated: (i) two different mechanisms that change the drive voltage, one due to the activation of Mg and one ascribed to the generation of point defects; (ii) a parasitic peak is present in the emission spectra, ascribed to the recombination in a second quantum well (QW); (iii) redistribution of charge takes place during the temperature step stress.