Study of predicting the performance of I-V curves through photoluminescence spectral characteristics

Quality of GaN LEDs is closely related to the defects in quantum wells. Effectively evaluating the performance of LEDs is a key step in mass production. Electrical characterization testing is very effective for characterizing the performance of LEDs, and the I-V curve is an important evaluation parameter. In this paper, we analyzed correlation in photoluminescence (PL) spectra and I-V curves among different LEDs and studied the feasibility of using PL to predict and estimate the characteristics of the I-V curves. Firstly, in the experiment, we varied the excitation light power and tested the photoluminescence (PL) spectral characteristics of different samples. Subsequently, I-V tests were conducted on these samples with current injection. The results of the I-V curve tests indicated significant differences among different samples, which were consistent with the PL results. Corresponding carrier transport model was established, and the I-V curves were fitted, resulting in different ideality factors for those samples. The results indicated that samples with lower photoluminescence intensity exhibited a larger ideality factor in the I-V curves. On the contrary, for samples with higher photoluminescence intensity, the resulting ideality factor is smaller, approaching 2. A deeper analysis reveals a negative correlation between the relative strength of the normal peak and the abnormal peak in photoluminescence spectra and the value of the ideality factor. In the future, based on this correlation, photoluminescence-based detection techniques can be used to predict the I-V curve characteristics of LEDs in scenarios where direct current injection is not feasible.