The impact of active layer design on quantum efficiency of InGaN light emitting diodes

Abstract The effect of active layer design on the efficiency of InGaN light emitting diodes (LEDs) with the light emission in blue (~420 nm) ha s been studied. Correlation between the internal quantum efficiency (IQE) and relative external quantum efficiency (EQE) and salient features of st ructures on c-plane InGaN LEDs which contain multiple quantum wells (MQWs) of different barrier height ( either In 0.01 Ga 0.99 N or In 0.06 Ga 0.94 N barriers ) and thicknes s (3 nm and 12 nm) as well as different double heterostructure (DH) designs (3 nm , dual 3 n m , 6 nm , dual 6 nm , 9 nm and 11 nm) with inserted 3 nm In 0.06 Ga 0.94 N barrier . Pulsed electroluminescence (EL) and optical excitation power -dependent photo luminescence (PL) measurements indic ated that the thinner and lower In 0.06 Ga 0.94 N barriers bode well for high EQE and IQE. Furthermore , increase of the effective active region thickness by multiple InGaN DH structures (dual, quad and hex) separated by 3 nm In