Orange-red light-emitting diodes based on a prestrained InGaN-GaN quantum-well epitaxy structure

The implementations of an orange and a red light-emitting diode (LED), which are fabricated with a prestrained InGaN-GaN quantum-well (QW) epitaxy structure, are demonstrated. The prestrain condition is created by growing a low-indium QW before the growth of five high-indium QWs. Without the prestrain condition, the five high-indium QWs of the same growth condition lead to green electroluminescence emission. With the prestrained growth, indium incorporation in the QWs grown after the low-indium one becomes higher and hence the orange-red LEDs can be fabricated for elongating the emission wavelength by more than 100 nm. Although the crystal quality and electrical properties of the orange-red LEDs may need to be improved, our results have shown the important effect of prestrained growth for elongating the LED wavelength.