Noise as a representation for reliability of light emitting diode

Abstract

Through the research of the internal structure of Light Emitting Diode (LED), we discovered that the interface trap density and diffusion current ratio are key factors determining the performance of LED, and they are also closely related to the reliability of LED. Among the many kinds of internal noises in LED, low-fre quency 1/f noise describes the interfoce trap density and diffuse current ratio effectively. Based on the mechanism of carrier number fluctuation and carrier mo bility fluctuation of 1/f noise, we put forward the electrical model and 1/f noi se model of LED. We also measured the electrical noise of the device over a wide range of current. Experimental results agree well with the proposed model. Usin g the experimental data, the relationship between noise and the performance and reliability of LED is established. It is proved that the larger the noise magnit ude, the nearer the current exponent is to 2, leading to the degradation of devi ce reliability and significant rise in device invalidation rate.