Molecular beam epitaxial CdTe/InSb(001) heterostructures were prepared by using various substrate temperatures, and were studied by using X-ray photo-electron spectroscopy and secondary ion mass spectrometry. The X-ray method showed that Te existed mainly as TeO2 at the sample surface, whereas In existed as In2O and In2O3. Both techniques directly revealed In interdiffusion. The secondary ion mass spectrometry depth profiles and the X-ray photo-electron spectroscopic 3d and 4d spectra of In indicated that the In concentration in CdTe films which were grown at high substrate growth temperatures was significantly higher than that in films which were grown using low substrate temperatures. This difference was attributed to the diffusion of In across the CdTe/InSb interface, from the InSb substrate. It was noted that dislocations also enhanced the diffusion of In from the InSb substrate. It was deduced that the CdTe and InSb lattices matched exactly at growth temperatures of about 180C, since the surface In concentration was a minimum for samples that had been grown using a substrate temperature of about 180C. The secondary ion mass spectrometric depth profiles of Te+ also revealed some evidence of Te diffusion across the interface, and into the substrate, in samples which had been grown using high substrate temperatures.

XPS and SIMS Studies of MBE-Grown CdTe/InSb(001) Heterostructures.  A.T.S.Wee, Z.C.Feng, H.H.Hang, K.L.Tan, R.F.C.Farrow, W.J.Choyke: Journal of Physics - Condensed Matter, 1995, 7[23], 4359-69

Table 3

Diffusivity of Ga in CuInSe2