Optical gain in InGaN∕GaN quantum well structures with embedded AlGaN δ layer

Abstract

Optical gain characteristics of $\mathrm{In}\mathrm{Ga}\mathrm{N}∕\mathrm{Ga}\mathrm{N}$ double quantum well (QW) structures with embedded AlGaN $\delta$ layer are investigated using the multiband effective mass theory. These results are compared with those of single QW structure without a $\delta$ layer. The theoretical energies show very good agreement with the experimental results for both single and double QW structures. The inclusion effect of a $\delta$ layer is found to be dominant at a relatively low carrier density. A double QW structure has larger optical gain than the single QW structure, in particular, at higher carrier density.