Analysis of Current Components and Estimation of Internal Quantum Efficiency in Light-Emitting Diodes

We have decomposed light-emitting diode (LED) current into component currents by identifying the ideality factor of each component and by fitting the measured and simulated current-voltage (
I
-
V
),
I
(
dV
/
dI
)-
I
and the shape of the relative luminescence efficiency-current characteristics. Nearly unity ideality factor of the radiative recombination current is found from luminescence-voltage (
L
-
V
) characteristics in AlGaInP red and GaInN green and blue LEDs. The current-component analysis enables an estimation of the internal quantum efficiency (IQE) as a function of current. Compared with red LEDs, blue LEDs suffer from lower radiative recombination efficiency and much larger efficiency droop to result in lower IQE.