Estimation of internal quantum efficiency in InGaN‐based light emitting diodes using electroluminescence decay times

We investigate the internal quantum efficiency of InGaN-based Light Emitting Diodes (LEDs) from the semiconductor rate equation of pulse current injection. A method is presented for estimating the internal quantum efficiency based on data of electroluminescence decay times measured as a function of current in the pulse injection. For the screening of built-in electric field, the pulse current was injected with bias voltage. For blue LED, the internal quantum efficiency was measured to be about 70% in high injection condition. It is found that the internal quantum efficiency increase with injection current, whereas the external quantum efficiency decreases at high injection. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)