Dependence of aging on inhomogeneities in InGaN/AlGaN/GaN light-emitting diodes

摘要

Changes of properties of green LEDs based on In{sub}xGa{sub}(1-x)N/Al{sub}yGa{sub}(1-y)/GaN heterostructures were studied during 150÷200 hours at currents I = 30÷80 MA. The radiation intensity at low currents (0.1÷1mA) is quite sensitive to such an aging, it falls down 10÷100 times. Quantum efficiency and spectral parameters at normal currents (J≈10 mA) change non-monotonically during aging, some degradation is observed after 168 hours. The degradation is observed also after a short (＜1 min) period of reverse current. These phenomena are discussed in terms of under threshold defect's formation and their migration in the space charge region of p-n-heterojunction. Potential fluctuations in the space charge region are quite sensitive to this process.