Fig. 6

Schematic diagrams indicating the possible mechanism of the anomalous variation of the PL peak energy vs. T curves with different excitation powers. The carrier distributions at lower T (10 K) are shown in (a) and (b) for P = 5 mW and 40 mW, respectively. The carrier distributions at higher T (30 K) are shown in (c) and (d) for P = 5 and 40 mW, respectively