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

Abstract

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 xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i> - <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> ), <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i> ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dV</i> / <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dI</i> )- <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</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 ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</i> - <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> ) 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.