InGaN based tunable green light-emitting diodes using InAlN interlayer and strain compensated AlGaN interlayer for better device performance

Abstract

The effect of employing an InyAl1−yN and AlyGa1−yN interlayer (IL) in the InxGa1−xN/GaN active region for the green light-emitting diodes (LEDs) has been studied. The high compressive strain in InxGa1−xN/GaN QW is compensated by the tensile strained AlyGa1−yN IL. The InyAl1−yN IL reduces the strain between InxGa1−xN and GaN layers. The AlyGa1−yN or the InyAl1−yN layer in between the QW and the GaN barriers increase the barrier height, which potentially suppresses the electron and hole leakage from the QW. These increase the square of the overlap of electron and hole wave functions (Meh2) of the QW LEDs. By changing the well width and aluminum or indium content in the IL, we obtained better optical properties. It has found that 10 Ǻ thick In0.2Al0.8N and 10 Ǻ thick Al0.8Ga0.2N layers give the maximum Meh2 for the green LEDs, using InyAl1−yN and AlyGa1−yN ILs. Furthermore, we have compared the Meh2, using AlyGa1−yN and InyAl1−yN IL with the current. The best result is obtained for the 10 Ǻ Al0.8Ga0.2N IL, which increases the Meh2up to 2 times, as compared to the QW LEDs, without any IL.