Optical and electrical properties of high brightness blue InGaN/GaN LEDs submitted to high direct current ageing and high power controlled electron beam irradiation in the SEM have been studied. The luminescence properties of the devices before and after the ageing were studied by SEM-cathodoluminescence, electroluminescence and Emission Microscopy while the effect of the ageing on the electrical properties was investigated by I-V characteristics and Deep Level Transient Spectroscopy. A good optical quality and homogeneity of the tested untreated devices was demonstrated by the low spread in the peak position and emission intensity of the 2.65 eV InGaN quantum well emission. Systematic DC-stressing treatments were carried out leading to a strong reduction in the InGaN active layer emission intensity, depending on the ageing conditions, and to the decomposition of complexes involving Mg in the p-type GaN layers. The influence of the stress on the Mg-related transitions was confirmed by low temperature optical studies. High power electron beam irradiation was performed in the SEM and the resulting changes of the luminescence properties have been investigated.
Luminescence properties of GaN LEDs after DC-aging
MENEGHESSO, GAUDENZIO;LEVADA, SIMONE;ZANONI, ENRICO;
2003
Abstract
Optical and electrical properties of high brightness blue InGaN/GaN LEDs submitted to high direct current ageing and high power controlled electron beam irradiation in the SEM have been studied. The luminescence properties of the devices before and after the ageing were studied by SEM-cathodoluminescence, electroluminescence and Emission Microscopy while the effect of the ageing on the electrical properties was investigated by I-V characteristics and Deep Level Transient Spectroscopy. A good optical quality and homogeneity of the tested untreated devices was demonstrated by the low spread in the peak position and emission intensity of the 2.65 eV InGaN quantum well emission. Systematic DC-stressing treatments were carried out leading to a strong reduction in the InGaN active layer emission intensity, depending on the ageing conditions, and to the decomposition of complexes involving Mg in the p-type GaN layers. The influence of the stress on the Mg-related transitions was confirmed by low temperature optical studies. High power electron beam irradiation was performed in the SEM and the resulting changes of the luminescence properties have been investigated.Pubblicazioni consigliate
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