Yellow-red light-emitting diodes using periodic Ga-flow interruption during deposition of InGaN well

We report a possible way to extend the emission wavelength of InyGa_1-yN/InxGa_1-xN quantum-well (QW) light-emitting diodes (LEDs) to the yellow-red spectral range with little degradation of the radiative efficiency. The InyGa_1-yN well with high indium (In) content (HI-InyGa_1-yN) was realized by periodic Ga-flow interruption (Ga-FI). The In contents of the HI-InyGa_1-yN well and the InxGa_1-xN barrier were changed to manipulate the emission wavelength of the LEDs. An In_0.34Ga_0.66N/In_0.1Ga_0.9N-QW LED, grown by continuous growth mode (C-LED), was prepared as a reference. The photoluminescence (PL) wavelengths of the HI-InyGa_1-yN/InxGa_1-xN QW LEDs were changed from 556 to 597 nm. The PL intensity of the HI-InyGa_1-yN/InxGa_1-xN LED with a peak wavelength of 563 nm was 2.7 times stronger than that of the C-LED (λ = 565 nm). The luminescence intensity for the HI-InyGa_1-yN/InxGa_1-xN QW LED emitting at 597 nm was stronger than those of the other LED samples with shorter wavelengths. Considering the previous works on degradation in crystal quality and increase in the quantum-confined Stark effect with increasing In content in InGaN, the approach in this work is very promising for yellow-red InGaN LEDs.