Redistribution of multi-quantum well states induced by current stress in InxGa1-xN/GaN light-emitting diodes

We report on the modification in the density of states of a multi-quantum well system of InGaN/GaN-based light emitting diodes. The modification was induced by dc current stress at I = 50 mA (current density J = 55 A cm−2) with stress times up to 100 h. The samples were characterized by means of current–voltage and capacitance–voltage, and photocurrent spectroscopy at different stress stages. We observed a progressive redistribution of the conduction band charge in the multi-quantum well system, along with a modification of the shape of the photocurrent spectrum