PACS: 68.55; 79.60.J; 73.50. P; 66.30.J

Distribution of components in epitaxial graded band gap heterostructures Cd(Mn,Zn)Te – Cd(Mn,Zn)HgTe and their photoelectrical properties

O. I. Vlasenko, V. M. Babentsov, Z. K. Vlasenko, A. V. Ponedilok
Institute of Semiconductor Physics, NAS Ukraine, 45 prospekt Nauki, Êyiv, 252028, Ukraine

I. V. Kurilo, I. O. Rudyj
State University “Lvivska Politekhnika”, 12 Stepan Bandera St., Lviv, 290646, Ukraine

V. V. Kremenitskiy
Technical Center, NAS Ukraine, 13 Pokrovska st., Kyiv, 254070, Ukraine

Abstract. By using the method of VPE CdMnTe-CdMnHgTe, CdZnTe-CdZnHgTe heterocompositions were fabricated. Increase of their photo-sensitivity in comparison with the CdTe-CdHgTe structure is explained by removal of deformation stresses due to introduction of isovalent component (Mn, Zn) of smaller size and due to reduction of recombination activity of non-equilibrium charge carriers in the film. Photo-sensitivity increase in the field of metallurgical boundary in the CdMnTe-CdMnHgTe structure under increase of the Mn contents up to ó £ 0,08 in comparison to the CdZnTe-CdZnHgTe structure is connected with more precise matching of lattices matching of the initial materials. Other models of this phenomena are also discussed, conditioned in particular, by the influence of micro- and macro- heterogeneities of the diffusion interface, peculiarities of P-T diagrams, etc. On the basis of comparison of experimental and calculated profiles of the components distribution, the values of diffusion coefficient in the substrate and growing film were obtained.

Keywords: graded band-gap films, photoconductivity, CdHgTe, CdMnHgTe, CdZnHgTe, vapor phase epitaxy, diffusion.

Paper received 02.10.98; revised manuscript received 22.10.98; accepted for publication 28.10.98.

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