Installation for Measuring of the Slope of the P-I Characteristic of the LED in the Range of the Electroluminescence Start Currents

Abstract

It is known that defects of InGaN/GaN LED heterostructure lead to a decrease of the slope of the light output power-current (P-I) characteristic of the LED. This is especially pronounced in microcurrent mode. An automated installation has been developed for measuring of the slope of the P-I characteristic of the LED in the current range of 5 µA … 3 mA. An example of a sample of green commercial LEDs shows the presence of a high correlation between the slope of the P-I characteristic and the defects density in the heterostructure of the LED. The measuring installation can be used in the system of quality control of LEDs.