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Fig. 6. Absorption response of the CuSe composite, left inset corresponds to the direct bandgap plot and right inset corresponds to indirect bandgap.

Figure 6 Absorption response of the CuSe composite, left inset corresponds to the direct bandgap plot and right inset corresponds to indirect bandgap.

Related Figures (6)

Fig. 1. Raman dispersion signal peaks obtained for the Cu-Se composite, where three frequencies have been identified by references.
Fig. 1. Raman dispersion signal peaks obtained for the Cu-Se composite, where three frequencies have been identified by references.
In Fig. 2 the Raman spectrum the bands at 411, 438 and 471 cm' for teineite (CuTeO3-2H,O) may be assigned to the E bending mode of (TeO 3)”, a possible assignment for the band at 775 cm would be antisymmetric stretching mode of TeO,. Typically the Raman band at 995 cm is associated to the symmetric stretching mode of (SO,)”, also the sharp Raman band at 1062 cm'' is due to the antisymmetric stretching mode of (SO4)” [13]. Is important to remark that typically the lattice vibrations appear from 10 to 200cm" region and the metallic with oxygen atom interaction are presented at the 200 to 450cm'' region [13]. Fig. 2. Raman dispertion signals peaks obtained for the Cu-Te composites, were indicated six frequencies values also by references.
In Fig. 2 the Raman spectrum the bands at 411, 438 and 471 cm' for teineite (CuTeO3-2H,O) may be assigned to the E bending mode of (TeO 3)”, a possible assignment for the band at 775 cm would be antisymmetric stretching mode of TeO,. Typically the Raman band at 995 cm is associated to the symmetric stretching mode of (SO,)”, also the sharp Raman band at 1062 cm'' is due to the antisymmetric stretching mode of (SO4)” [13]. Is important to remark that typically the lattice vibrations appear from 10 to 200cm" region and the metallic with oxygen atom interaction are presented at the 200 to 450cm'' region [13]. Fig. 2. Raman dispertion signals peaks obtained for the Cu-Te composites, were indicated six frequencies values also by references.
Fig. 3. XPS survey for cooper-selenium composite, while the inset depicts the selenium presence. reference [14]. The kinetic energy of Cu L3wv peak is 965.5 eV, therefore, the value of the modified Auger parameter is 995.5 eV, which can be used to differentiate it from CuSe and Cu2Se, and the modified Auger parameter is close to that of Cu(1), this XPS feature should arise from main Cu(l) and diminish Cu(II) valence states. The chemical composition of this material can be deduced as CuSe with copper in the +2 oxidation state.
Fig. 3. XPS survey for cooper-selenium composite, while the inset depicts the selenium presence. reference [14]. The kinetic energy of Cu L3wv peak is 965.5 eV, therefore, the value of the modified Auger parameter is 995.5 eV, which can be used to differentiate it from CuSe and Cu2Se, and the modified Auger parameter is close to that of Cu(1), this XPS feature should arise from main Cu(l) and diminish Cu(II) valence states. The chemical composition of this material can be deduced as CuSe with copper in the +2 oxidation state.
Fig. 4. XPS survey for the copper-tellurium composite, while the inset depicts two peaks of tellurium. Also, in Fig. 4 the maxima for Te 3d5 corresponding to the binding energy value of 575.5 >V, which show the presence of telluride ion, while the peak in 587 eV corresponds to TeO, or Te IV). In other words, the lower binding energy corresponds to the oxidation state Te” and the 1igher one to oxides, where the oxidation state is Te”. So the Te 3d region shows that the valence of Te is -2, while the Cu 3p region show valence for the copper of +1.
Fig. 4. XPS survey for the copper-tellurium composite, while the inset depicts two peaks of tellurium. Also, in Fig. 4 the maxima for Te 3d5 corresponding to the binding energy value of 575.5 >V, which show the presence of telluride ion, while the peak in 587 eV corresponds to TeO, or Te IV). In other words, the lower binding energy corresponds to the oxidation state Te” and the 1igher one to oxides, where the oxidation state is Te”. So the Te 3d region shows that the valence of Te is -2, while the Cu 3p region show valence for the copper of +1.
Fig. 5. Micrographs of Cu-Se and Cu-Te composites, the up pair corresponds to the Cu-Se composite, where to the left it is shown a representative contrast image and to the right a higher magnification. The down pair corresponds to the similar for Cu-Te compound. I Beside each TEM contrast image is displayed the diffraction pattern corresponding, which indicates orthorhombic structures for both samples. Because the interplanar distances 3.208 A, 3.026 A, 2.029 A and 1.906 are characteristic of this type structure for the Cuz,Se according to JCPDS card number 27-0184, and d = 3.514 A is characteristic for CuTe from JCPDS card number 22-0252.
Fig. 5. Micrographs of Cu-Se and Cu-Te composites, the up pair corresponds to the Cu-Se composite, where to the left it is shown a representative contrast image and to the right a higher magnification. The down pair corresponds to the similar for Cu-Te compound. I Beside each TEM contrast image is displayed the diffraction pattern corresponding, which indicates orthorhombic structures for both samples. Because the interplanar distances 3.208 A, 3.026 A, 2.029 A and 1.906 are characteristic of this type structure for the Cuz,Se according to JCPDS card number 27-0184, and d = 3.514 A is characteristic for CuTe from JCPDS card number 22-0252.
Fig. 7. Absorption response of the CuSe composite, left inset corresponds to the direct bandgap calculation and right inset corresponds to indirect bandgap.
Fig. 7. Absorption response of the CuSe composite, left inset corresponds to the direct bandgap calculation and right inset corresponds to indirect bandgap.
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