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

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.

Unstable mixing regions in II-VI quaternary solid solutions

“…Fig. 1 also presents experimental points from different papers [2,3,5,6,18 ] obtained from epitaxial layers deposition by LPE and MOVPE techniques, demonstrating good agreement with the calculations, i.e., no experimental points fall in the thermodynamic instability region at the epitaxy temperature. When the layer thickness decreases, the strain effect increases and the miscibility gap narrows.…”

“…The technological difficulties of growing CdMnHgTe and ZnMnHgTe solid solutions [2] hampered its wide introduction into practice until recently. However, the recent achievements in this area [3][4][5] opened new prospects for its production and application. Moreover, it is worth noting the growing interest in such fundamental characteristics as electronic band structure [6], transport [4], magnetic [7], optical [5] properties of specified materials.…”