Optical Properties of Green InGaN/GaN Quantum-Well Light-Emitting Diodes with Embedded AlGaN δ Layer

The optical characteristics of green InGaN/GaN double-quantum-well (QW) structures with embedded AlGaN delta layers are investigated using the multiband effective mass theory. These results are compared with those of single QW structure without a delta layer. A double QW structure has a much larger spontaneous emission than a single QW structure for a relatively thick well width (L(w) = 5 nm) because a double QW structure has a larger optical matrix element and a smaller effecive well width than a single QW structure. The inclusion effect of a delta layer is found to be dominant at a relatively thick well width. However, the double QW structure is shown to need a slightly larger In composition to obtain the same transition wavelength as the single QW structure.