Non-ideal characteristic analysis of GaN-based light-emitting diode using current-voltage (I-V) and low-frequency noise experiment

In order to investigate the reliability problem of the GaN-based light-emitting diode (LED), the non-ideal characteristics of the GaN-based LED were analyzed through current-voltage (I-V) and low-frequency noise experiment. Ideality factor, parasitic resistance and parasitic diode were considered to analyze the I-V characteristic. We could find that the parasitic diode makes the forward hump and divides the I-V curve into the parasitic and the main part. Those two parts have much different ideality factor and series resistance value, respectively. Power spectral density (PSD) with various frequency and current were measured to examine the noise characteristic. We could find the high level and the steep slope of the PSD at low currents, which indicate the unstable noise characteristic.