Wave functions of a direct exciton at state E₁ (a), at state E₂ (b) for ADQW1, at state E₁ (c), and at state E₂ (d) for ADQW2 with L_b1 = 7 nm, L_w1 = 5 nm, L_b = 1.8 nm, L_w2 = 3 nm, L_b2 = 4 nm, xl = 0.6, xc = xr = 0.4, and that of an indirect exciton at state E₁ (e), and at state E₂ (f) for ADQW2 with L_b1 = 7 nm, L_w1 = L_w2 = L_b2 = 4 nm, L_b = 1.8 nm, xl = 0.6, xc = xr = 0.4. The unit a.u. is short for arbitrary units.