Ordering of In and Ga in epitaxially grown In_0.53Ga _0.47As films on (001) InP substrates

Ordering of In and Ga in In_0.53Ga_0.47As films grown at 573 K, 673 K, and 773 K by molecular beam epitaxy was investigated by electron diffraction pattern analysis using a transmission electron microscope equipped with an Ω-filter and imaging plates. In addition, high-resolution electron microscopy on the specimens and fast Fourier transformation analyses were performed to identify the short-range ordering. In the EDPs obtained from the specimen grown at 573 K, the diffuse scattering corresponding to short-range ordering was observed only when the film was investigated at [110] beam incidence, whereas for the specimens grown at 673 and 773 K, diffuse scattering was observed only at [110] beam incidence. The ordering of 573 K specimen has a triple period and those of 673 K and 773 K have a double period. Through the processing of the HREM images and comparison of calculated and observed diffuse-scattering distribution, models of short-range ordered structures were proposed on the basis of the triple-A type ordering at the specimen grown at the 573 K and the CuPt-B type ordering at the specimen grown at 773 K.