ABSTRACT
A Transmission electron microscopy (TEM) fitted with a cathodoluminescence (CL) light collector and an optical spectrometer has been used to investigate spatially and spectrally resolved luminescence phenomena in two epitaxial nitride systems. Using diffraction contrast imaging and monochromatic CL linescans in the TEM it was shown that this emission is directly correlated to intrinsic basal plane stacking faults in the GaN. Use of a TEM equipped with a scanning attachment and coupled with a cathodoluminescence light collector/spectrometer system offers the possibility of correlating microstructural information with spatially resolved spectroscopy. The substrates were (0001) sapphire, there was a low temperature GaN nucleation layer followed by a buffer layer grown at 1140°C. InGaN quantum wells grown at 832°C were nominally 2.5nm thick and capped with 15nm of GaN. CL spectroscopy in the TEM showed weaker emission at this wavelength than might be expected owning to the small volume of material excited.
