Internal Quantum Efficiency and Carrier Injection Efficiency of c-plane, {101̄1} and {112̄2} InGaN/GaN-Based Light Emitting Diodes

The electroluminescence (EL) output power of c-plane light emitting diodes (LEDs) is much higher than that of semipolar {101̄1} and {112̄2} LEDs on sapphire at the same operation current. In order to elucidate the reasons for this behavior, we have fitted the pulsed EL data by the well-known ABC model to extract the internal quantum efficiency (IQE) and the carrier injection efficiency (CIE) to clarify which parameter weighs more for the poor EL output power of the semipolar LEDs. On our semipolar LEDs, we observe a CIE of only about 4%, whereas their c-plane counterparts show a CIE of nearly 80%. The IQE values are fairly the same for all three structures. The fit of resonant photoluminescence (PL) data at room temperature confirms the similar IQE values for all three structures.