Impact of the Surface Leakage Current on the Internal-Quantum-Efficiency Measurement of Light-Emitting Diodes by the Room-Temperature Reference-Point Method

Abstract

Measurement of the internal quantum efficiency (IQE) is of critical importance in evaluating and improving the characteristics of light-emitting diodes (LEDs). Among various methods of measuring the IQE, the room-temperature reference-point method (RTRM) is frequently employed owing to many advantages such as the ease of applicability and measurement speed. The RTRM evaluates the IQE from the light-current (L-I) characteristics without any prior assumption of physical parameters and only with relative radiant power values. In this study, we analyze the effect of the surface leakage current on the RTRM by using a blue LED with the simulated surface leakage using a resistor connected in parallel with the LED. By varying the values of the parallel resistance from 1 M Omega to 1 k Omega , we examine the changes in various optoelectronic characteristics, namely, current-voltage (I-V), L-I, the ideality factor, and the a2 coefficient of the RTRM. This paper serves as a case study for understanding the effect of surface leakage current on the optoelectronic characteristics of the LED. A guideline is proposed for the applicability of the RTRM in measuring the IQE values of the LED and possibly the micro-LED so that the method can be utilized more reliably.