“…The introduction of indium in the barrier material of Sample B reduces the strain at the QW-barrier interface, further lowering the inhomogeneity of the Ga 1−x In x N y As 1−y QWs in the sample. 6,9 Hence, the effect of carrier localization is expected to be much stronger in Sample A, while the period of the modulation is larger in Sample B. The result is that, in both samples, the electrons may be trapped by nitrogen-rich 24,31 regions, while the holes may only be localized in In-rich parts of the sample, separating them from electrons in the N-rich regions at low temperatures in an out-of-phase manner (Fig.…”