The combined spectral image is rendered through a color coded plot of Raman (green) and photoluminescence (red) signal strength over the corresponding color bracketed Raman shift positions shown in the upper traces. The perimeter of the crystal appears green because of the absence of photoluminescence at that location. The separate Raman and photoluminescence images show the spatially varying differences in solid state structure as revealed through vibrational and electronic spectroscopies.