Leakage Current Analysis of GaN-Based Light-Emitting Diodes Using a Parasitic Diode Model

The leakage current of GaN-based light-emitting diodes (LEDs) was analyzed with a parasitic diode model. Arrhenius plots of forward leakage currents revealed that the threshold voltages of the main diode and the parasitic diode were 2.64 and 0.94 V, respectively. The parasitic diode, however, led to an insignificant change in the reverse leakage mechanism, e.g., a predominant reverse leakage mechanism was Poole-Frenkel conduction in the high-temperature range (>300 K) and the variable range hopping in the low-temperature range (<;300 K), as reported previously. The origin of the parasitic diode could be due to the incorporated hydrogen (H) atoms into the top LEDs layers, presumably enhancing the defect-assisted tunneling through the generated H-related deep-level states, particularly generated in the p-cladding or p-AlGaN electron blocking layer.