Cubic substrates

The cubic zincblende phase of GaN (lattice parameter of about 4.5 A) is a metastable one and observed only for heteroepitaxial layers on highly mismatched cubic substrates (OOl)-oriented, for example GaAs [11], Si [12], MgO [13] and p-SiC [14],... 

Transmission electron microscopy (TEM) is a powerful tool for analysing the crystal structure since information on both microstructures and diffractograms for local areas in film specimens can be obtained. There are already relevant reviews concerning Ill-nitrides grown on GaAs and other cubic substrates [1-4]. In this Datareview, therefore, studies on GaN/GaAs with TEM work are summarised with reference to the phase selection of h-GaN and c-GaN, the heterointerface and defects. 

H. Okumura [ Datareview in this book B2.6 Cubic substrates for growth of GaN and related compounds ]... 

That final state scattering is of importance has been shown by Liebsch (53) and Liebsch and Plummer (54) who have performed calculations for a model system consisting of a localised s-type adsorbate orbital on a simple cubic substrate. The appropriate Bloch character of the final state wave function is taken into account within a multiple scattering theory such as has been applied in LEED calculations. 

Fig. 12.5. Schematic of the (103) domain structure on the (101) cubic substrate. Tilt boundaries occur along the [301] direction twist boundaries occur along the [010] direction.

Fig. 7.3. Pyramid of 111 planes in a cubic film material epitaxially bonded to a cubic substrate with a (001) interface. The planes represent potential glide planes for strain relieving dislocations in the film, and the edges of the pyramid extending from the apex identify the directions of possible Burgers vectors of 60° dislocations. The edges of the cube cell are identified by the triad of crystallographic vectors.

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