ABSTRACT
This chapter examines the composition and thickness of a set of InGaN/GaN multiple quantum wells as deduced from low and highresolution x-ray diffraction (XRD) rocking curves of the out of plane reflection using energy filtered transmission electron microscopy (EFTEM) and highangle annular dark-field imaging. It shows that where variations in well and barrier thickness occur the XRD/ transmission electron microscope agreement is poor, but that statistical variations in the indium concentration are relatively benign. Since the inception of InGaN/GaN multiple quantum wells for optoelectronic devices, x-ray diffraction has been used extensively for structural analysis. In the bright-field image, Fresnel fringes associated with the interfaces may have been strong, but in the EFTEM images were heavily damped. Reasonable agreement occurs for the HAADF/XRD well width measurements, but some disagreement does occur for the EFTEMIXRD composition data, with EFTEM giving indium concentrations several percent lower.
