Figure 5

The variation of FWHM for samples I, II, and III as a function of injection current.
The FWHM decreases at the low injection current region (yellow region), while it increases again with increasing injection current (white region). The former can be explained by the screening effect of internal electric field, while the latter by the band filling effect. We confirmed that the influence of the screening and band filling in QW was reduced with decreasing the barrier thickness.