Figure 5

Absorption spectra of the 50-periods InGaN digital alloys: set (a) 1 ML GaN with 1, 2, 3, 4 MLs InN, respectively; set (b) 2 MLs GaN with 1, 2, 3, 4 MLs InN, respectively; set (c) 3 MLs GaN with 1, 2, 3, 4 MLs InN, respectively; and set (d) 4 MLs GaN with 1, 2, 3, 4 MLs InN, respectively.