Figure 4

Photoluminescence results. (a) The microscope image of GeSn stripe patterns for photoluminescence (PL) test. The incident light was focused into a spot of ~20 μm using a 15× objective, and A, B, C,D and E are the positions of focused light spot in the course of PL test, and the PL results of position A, B, C and D at room temperature (300 K) are plotted in (b). (c) The temperature-dependent PL results of position E.