Electronic and optical properties of ZnSe by theoretical simulation TB-mBJ (Tran-Blaha modified Becke Johnson) associated to analysis techniques XPS (X-Ray Photoelectron Spectroscopy); REELS (Reflective Electron Energy Loss Spectroscopy) and PLS (Photoluminescence Spectroscopy)

Halati, Mohamed Salah; Benchenane, Halima; Bouslama, M.; Mokadem, A.; Ouerdane, A.; Bedjaoui, A.; Bouhemadou, A.; Guezzoul, M’hamed; Kharoubi, Bachir; Abdelkrim, Mahfoud; Bensassi, Kadda Benmohktar; Baizid, Abdelhak

doi:10.1016/j.apsusc.2021.150690

“…Aiming to explore structural and thermodynamic stabilities of the quaternary Tl 2 HgGeSe 4 compound, both cohesive energy ( ) and formation enthalpy ( ) have been evaluated. The first one is described as the energy required when a system decomposes into free atoms, employing the following relationship 46 : where , , , and refer to the total energy of the Tl 2 HgGeSe 4 primitive cell and the total energies of the isolated Tl(Thallium), Hg(Mercury), Ge(Germanium) and Se(Selenium) atoms, respectively. We calculated the free energy of the above atoms considering a cubic box which has a large lattice constant (a Å) that contains the considered atom.…”

Section: Resultsmentioning

confidence: 99%

“…So, the predictive cohesive energy is equal to using the so-called generalized gradient approximation functional of Perdew-Burke-Ernzerhof (GGA-PBEsol08). The second one was the formation enthalpy ( ) which is described as the energy needed to form a system from its constituent elements in their most stable state as following 46 : where , , and refer to the total energy of the “face-centered cubic Tl”, “body-centred tetragonal Hg”, “body-centred cubic Ge” and “hexagonal close packed Se” solids, respectively. The formation energy ( ) is equal to as determined using the same exchange and correlation potential.…”

Section: Resultsmentioning

confidence: 99%

Structural, elastic, electronic, optical and anisotropy properties of newly quaternary Tl2HgGeSe4 via DFPT predictions associated to XPES and RS experiments

Halati,

Khyzhun,

Khireddine

et al. 2024

Sci Rep

1

0

1

View full text Add to dashboard Cite

In the present work, we report on theoretical studies of thermodynamic properties, structural and dynamic stabilities, dependence of unit-cell parameters and elastic constants upon hydrostatic pressure, charge carrier effective masses, electronic and optical properties, contributions of interband transitions in the Brillouin zone of the novel Tl2HgGeSe4 crystal. The theoretical calculations within the framework of the density-functional perturbation theory (DFPT) are carried out employing different approaches to gain the best correspondence to the experimental data. The present theoretical data indicate the dynamical stability of the title crystal and they reveal that, under hydrostatic pressure, it is much more compressible along the a-axis than along the c-axis. Strikingly, the charge effective mass values ($$m_{e}^{{^{*} }}$$ m e ∗ and $$m_{h}^{{^{*} }}$$ m h ∗ ) vary considerably when the high symmetry direction changes indicating a relative anisotropy of the charge-carrier’s mobility. Furthermore, the Young modulus and compressibility are characterized by the maximum and minimum values ($$E^{max}$$ E max and $$E^{\min }$$ E min ) and ($$\beta^{max}$$ β max and $$\beta^{\min }$$ β min ) that are equal to (62.032 and 28.812) GPa and (13.672 and 6.7175) TPa–1, respectively. Additionally, we have performed calculations of the Raman spectra (RS) and reached a good correspondence with the experimental RS spectra of the Tl2HgGeSe4 crystal. The XPES associated to RS constitutes powerful techniques to explore the oxidized states of Se and Ge in Tl2HgGeSe4 system.

show abstract

“…Additionally, the survey spectra show the signals related to Zn and Cd atoms (Zn-2p, Zn-3d, Zn-3s and Zn LMM Auger transition lines for 3F and 4F , and Cd-2s, Cd-3p, Cd-3d, Cd-4p, Cd-4d, Cd MNN transition lines for 5F and 6F ), as well as to selenium (Se-3d, Se-3p, Se-4p and the Se LMM Auger transition lines) in agreement with reported studies. 60,62–65…”

Section: Thin Filmsmentioning

confidence: 99%

“…Additionally, the survey spectra show the signals related to Zn and Cd atoms (Zn-2p, Zn-3d, Zn-3s and Zn LMM Auger transition lines for 3F and 4F, and Cd-2s, Cd-3p, Cd-3d, Cd-4p, Cd-4d, Cd MNN transition lines for 5F and 6F), as well as to selenium (Se-3d, Se-3p, Se-4p and the Se LMM Auger transition lines) in agreement with reported studies. 60,[62][63][64][65] For Zn-containing samples, the Zn-2p features were fitted with a spin-orbit doublet (p-type curve), arising from Zn-2p 3/2 and Zn-2p 1/2 (D spin-orbit splitting = 23.1 eV), located at binding energies (BEs) of 1022.20 eV and 1045.30 eV for 3F and 1022.08 eV and 1045.18 eV for 4F, proving the presence of Zn in its Zn 2+ oxidation state. 60,66 These data agree well with those reported for Zn-2p peaks from ZnS x Se 1Àx films (with different x composition (x = 0.4, 60 0.24, 67 0.6-1, 68 and x = 1, 0.75, 0.55, and 0.35 66 ) and ZnSe, 65,69,70 respectively.…”

Section: Xps Analysismentioning

confidence: 99%

“…Thus, the detected broad emissions may be ascribed to the DD emission band that could be originated by donor-acceptor pair transitions resulting from species related to the P content. 5,64,98 In addition, there was a strong quenching of PL signals after annealing, which can be due to size increase inducing the outward diffusion of interstitial defects at the surface, decreasing emissions of both interstitial defects and surface states.…”

Section: Photoluminescence Studies (Pl)mentioning

confidence: 99%

See 1 more Smart Citation