STRUCTURE MODULATION OF AL0.5IN0.5P STUDIED BY ENERGY-FILTERED ELECTRON-DIFFRACTION AND HIGH-RESOLUTION ELECTRON-MICROSCOPY

Structure modulation of a III-V alloy semiconductor Al0.5In0.5P was in vestigated by electron diffraction and high-resolution electron micros copy (HREM). By utilizing an energy filter, the background of the elec tron diffraction patterns was markedly reduced and two types of the di ffuse scattering were clearly revealed. One type of diffuse scattering is situated at the midpoint of the fundamental reflections while the other type is situated around the fundamental reflections. From the an alysis of the HREM image, the structure modulation is interpreted to r esult from the ordering and the concentration modulation of Al and in. Furthermore, a structure model of Al0.5In0.5P is derived from the HRE M image, and diffraction intensity calculated based on the structure m odel shows good agreement with the observed intensity.