No abstract available

No abstract available

[en] Impurity luminescence in CdSe thin single crystal layers and bulk samples was investigated. Epitaxial CdSe layers were prepared by chemical transport reaction method in an open CdSe-H₂ system in a double-zone oven with wide variation of growth conditions. Sapphire and fluorite were used as supports. Layer crystallinity was checked by means of X-ray and electronographic methods. The study of intensity of the long-wave emission bands (lambda sub(m)=0.72, 0.81-0.82, 0.93-0.94 and 1.20 mcm) versus temperature showed that they are due to centers Esub(v)+0.06, Esub(v)+0.27, Esub(v)+0.48 and Esub(v)+0.60 eV. Existence of these centers in investigated CdSe samples is evident from photosensitivity and absorption on the same samples at 80-300 deg K. Emission at 0.82, 0.93 and 1.2 mcm is a result of electron capture from conductivity zone to centers Esub(v)+0.12, Esub(v)+0.48 and Esub(v)+0.60 eV. The change of luminescence intensity in the bands 0.93 and 1,2 mcm after annealing the samples in Se vapour may be explained by change of concentration or degree of occupation of the luminescence centers. Increase of intensity of impurity luminescence in the bands 0.93 and 1.2 mcm in the samples annealed at lower Se vapour pressure explained by the change of centers Esub(v)+0.48 and Esub(v)+0.6 eV concentrations should be associated (on the basis of thermal treatment conditions) with Cd vacancies or their complexes. Decrease of emission intensity in the bands 0.93 and 1.20 mcm in the samples annealed at the higher Se vapour pressure may be due to a decrease of concentration of degree of occupation of the centers Esub(v)+0.48 and Esub(v)+0.60 eV

[en] Heterojunctions ZnTe-CdSe, ZnTe-CdS, ZnTe-CdSsub(x)Sesub(1-x) have been prepared and studied by means of an electron sonde and electroluminescence. Epitaxial layers of CdSe on oriented plates of ZnTe are grown by the method of a chemical transport reaction in the open system where purified hydrogen is used as a carrier and reagent. The substance to be evaporated is CdSe. The study of cathodoluminescence of cleaved surfaces of heterojunctions ZnTe-CdSe and ZnTe-CdS by a thin electron sonde shows that there exists the region of solid solutions in heterojunctions of such a type. Epitaxial heterojunctions ZnTe-CdX are structures of the type p⁺-p-n-n⁺. The study of spectra of electroluminescence of heterojunctions which are characterized by the region of negative resistance in the volt-ampere curve and photoluminescence of epitaxial films at 77 deg K allows the presence of radiation maxima to be established both for ZnTe and CdX. Heterojunctions ZnTe-CdSe on the basis of non-alloyed materials change the colour of luminescence from green to red on switching. A possibility is shown of preparation of luminescent diodes with preferential injection into ZnTe (green sources) and into CdSe (red sources)