Ukrainian Journal of Physical Optics 

Volume 22, Issue 2, 2021

Home page

Other articles 

in this issue
Electronic band structure of cubic solid-state CdTe1–xSex solutions

1Ilchuk H.A., 2Andriyevsky B., 3Kushnir O.S., 1*Kashuba A.I., 1Semkiv I.V. and 1Petrus R.Yu.

1Department of General Physics, Lviv Polytechnic National University, 12 Bandera   Street, 79046 Lviv, Ukraine. *
2Faculty of Electronics and Computer Sciences, Koszalin University of Technology,   2 Sniadeckich Street, 75-453 Koszalin, Poland
3Electronics and Computer Technologies Department, Ivan Franko National   University of Lviv, 107 Tarnavsky Street, 79005 Lviv, Ukraine 

Download this article

Abstract. We report on the electronic band structure of solid-state solutions CdTe1–xSex (CTS, 0 < x ≤ 5/16) calculated in the framework of density functional theory. The structure of CTS is calculated following from the ‘parent’ binary compound CdTe, which is crystallized in a cubic phase. The bandgap of CTS is found to be of a direct type for all of the solid-state solutions under test. A decrease in the bandgap Eg is found with increasing selenium content x. The Eg(x) dependence reveals some deviations from a simple linear function. The free-carrier concentration increases with increasing selenium content. It is shown that interaction among the atoms of host matrix (CdTe) and substitution selenium atoms causes splitting of the valence bands into heavy-hole and light-hole subbands and spin-orbit splitting, while the conduction bands remain unaffected. The dependence of refractive index on the selenium content is obtained

Keywords: solid-state solutions, CdTe, concentration dependences, electronic band structure, carrier concentration, refractive index

UDC: 544.225.22, 621.315.592, 535.323
Ukr. J. Phys. Opt. 22 101-109
doi: 10.3116/16091833/22/2/101/2021
Received: 22.02.2021

Анотація. У рамках теорії функціонала густини розраховано електронну зонну структуру твердотільних розчинів CdTe1–xSex (CTS, 0 < x ≤ 5/16). Структуру CTS одержано, виходячи з «материнської» бінарної сполуки CdTe, яка кристалізується в кубічній фазі. Встановлено, що всі вивчені нами твердотільні розчини CTS є прямозонними. Виявлено звуження ширини щілини Eg зі зростанням вмісту селену x. Залежність Eg(x) дещо відхиляється від лінійної. Концентрація вільних носіїв зростає зі зростанням вмісту селену. Показано, що взаємодія між атомами матриці-господаря (CdTe) та атомами заміщення селену викликає розщеплення валентних смуг на важкі діркові та легкі діркові підзони, а також спін-орбітальне розщеплення, тоді як смуги провідності залишаються незмінними. Одержано залежність показника заломлення від вмісту селену.

  1. Romeo N, Bosio A, Tedeschi R and Canevari V, 2000. Growth of polycrystalline CdS and CdTe thin layers for high efficiency thin film solar cells. Mater. Chem. Phys. 66: 201-206. doi:10.1016/S0254-0584(00)00316-3
  2. McCandless B E and Dobson K D, 2004. Processing options for CdTe thin film solar cells. Sol. Energy. 77: 839-856. doi:10.1016/j.solener.2004.04.012
  3. Treharne R E, Seymour-Pierce A, Durose K, Hutchings K, Roncallo S and Lane D, 2011. Optical design and fabrication of fully sputtered CdTe/CdS solar cells. J. Phys.: Conf. Ser. 286: 012038. doi:10.1088/1742-6596/286/1/012038
  4. Basola B M and McCandless B, 2014. Brief review of cadmium telluride-based photovoltaic technologies. J. Photon. Energy. 4: 040996. doi:10.1117/1.JPE.4.040996
  5. Romeo N, Bosio A, Canevari V and Podesta A, 2014. Recent progress on CdTe/CdS thin film solar cells. Sol. Energy. 77: 795-801. doi:10.1016/j.solener.2004.07.011
  6. Paudel N R, Xiao C and Yan Y, 2014. Close-space sublimation grown CdS window layers for CdS/CdTe thin-film solar cells. J. Mater. Sci.: Mater. Electron. 25: 1991-1998. doi:10.1007/s10854-014-1834-1
  7. Petrus R, Ilchuk H, Kashuba A, Semkiv I and Zmiiovska E, 2020. Optical properties of CdTe thin films obtained by the method of high-frequency magnetron sputtering. Funct. Mater. 27: 342-347. doi:10.15407/fm27.02.342
  8. Ilchuk H, Petrus R, Kashuba A, Semkiv I and Zmiiovska E, 2020. Optical-energy properties of CdSe thin film. Mol. Cryst. Liq. Cryst. 699: 1-8. doi:10.1080/15421406.2020.1732532
  9. Il'chuk G A, Petrus R Yu, Kashuba A I, Semkiv I V and Zmiiovs'ka E O, 2020. Peculiarities of the optical and energy properties of thin CdSe films. Opt. Spectrosc. 128: 50-57. doi:10.1134/S0030400X20010105
  10. Ilchuk H A, Petrus R Yu, Kashuba A I, Semkiv I V and Zmiiovska E O, 2018. Optical-energy properties of the bulk and thin-film cadmium telluride (CdTe). Nanosystems, Nanomaterials, Nanotechnologies. 16: 519-533. doi:10.15407/nnn.16.03.519
  11. Kale R B and Lokhande C D, 2005. Band gap shift, structural characterization and phase transformation of CdSe thin films from nanocrystalline cubic to nanorod hexagonal on air annealing. Semicond. Sci. Technol. 20: 1. doi:10.1088/0268-1242/20/1/001
  12. Kainthla R C, Pandya D K and Chopra K L, 1980. Solution growth of CdSe and PbSe films. J. Electrochem. Soc. 127: 277. doi:10.1149/1.2129655
  13. Poplawsky J D, Guo W, Paudel N, Ng A, More K, Leonard D and Yan Y, 2016. Structural and compositional dependence of the CdTexSe1-x alloy layer photoactivity in CdTe-based solar cells. Nature Commun. 7: 12537. doi:10.1038/ncomms12537
  14. Reshak A H and Jamal M, 2017. Investigation of pressure-induced phase transitions of the solar cell materials CdTexSe1-x alloys: one- and two-dimensional search DFT calculation. Phase Trans. 90: 1155-1166. 
  15. Jamal M, Abu-Jafar M S and Dahliah D, 2017. Disclosing the structural, phase transition, elastic and thermodynamic properties of CdTexSe1-x (x = 0.0, 0.25, 0.5, 0.75, 1.0) using LDA exchange correlation. Results in Physics. 7: 2213-2223. doi:10.1016/j.rinp.2017.06.033
  16. Shakil M, Zafar M, Ahmed S, Hashmi R M, Choudhary M A and Iqbal T, 2016. Theoretical calculations of structural, electronic, and elastic properties of CdTexSe1-x: A first principles study. Chin. Phys. B. 25: 076104. doi:10.1088/1674-1056/25/7/076104
  17. Reshak A H, Kityk I V, Khenata R and Auluck S, 2011. Effect of increasing tellurium content on the electronic and optical properties of cadmium selenide telluride alloys CdTexSe1-x: An ab initio study. J. Alloys and Comp. 509: 6737-6750. doi:10.1016/j.jallcom.2011.03.029
  18. Ouendadji S, Ghemid S, Bouarissa N, Meradji H and El Haj Hassan F, 2011. Ab initio study of structural, electronic, phase diagram, and optical properties of CdTexSe1-x semiconducting alloys. J. Mater. Sci. 46: 3855-3861. doi:10.1007/s10853-011-5306-1
  19. Kashuba A I, Ilchuk H A, Petrus R Yu, Andriyevsky B, Semkiv I V and Zmiyovska E O, 2021. Growth, crystal structure and theoretical studies of energy and optical properties of CdTexSe1-x thin films. Appl. Nanosci. doi:10.1007/s13204-020-01635-0 
  20. Ilchuk H A, Korbutyak D V, Kashuba A I, Andriyevsky B, Kupchak I M, Petrus R Yu and Semkiv I V, 2020. Elastic properties of CdTexSe1-x (x = 1/16) solid solution: first principles study. Semicond. Phys., Quant. Electron. & Optoelectron. 23: 355-360. doi:10.15407/spqeo23.04.355
  21. Andriyevsky B, Kashuba A I, Kunyo I M, Dorywalski K, Semkiv I V, Karpa I V, Stakhura V B, Andriyevska L, Piekarski J and Piasecki M, 2019. Electronic bands and dielectric functions of In0.5Tl0.5I solid state solution with structural defects. J. Electron. Mater. 48: 5586-5594. doi:10.1007/s11664-019-07404-2
  22. Clark S J, Segall M D, Pickard C J, Hasnip P J, Probert M J, Refson K and Payne M C, 2005. First principles methods using CASTEP. Z. Kristallogr. 220: 567-570. doi:10.1524/zkri.220.5.567.65075
  23. Perdew J P, Ruzsinszky A, Csonka G I, Vydrov O A, Scuseria G E, Constantin L A, Zhou X and Burke K, 2008. Restoring the density-gradient expansion for exchange in solids and surfaces. Phys. Rev. Lett. 100: 136406. doi:10.1103/PhysRevLett.100.136406
  24. Monkhorst H J and Pack J D, 1976. Special points for Brillouin-zone integrations. Phys. Rev. B. 13: 5188. doi:10.1103/PhysRevB.13.5188
  25. Turko B, Mostovoy U, Kovalenko M, Eliyashevskyi Y, Kulyk Y, Bovgyra O, Dzikovskyi V, Kostruba A, Vlokh R, Savaryn V, Stybel V, Tsizh B and Majevska S, 2021. Effect of dopant concentration and crystalline structure on the absorption edge in ZnO:Y films. Ukr. J. Phys. Opt. 22: 31-37. doi:10.3116/16091833/22/1/31/2021
  26. Freik D M, Chobanyuk V M, Krunutcky O S and Gorichok I V, 2012. Photovoltaic solar energy converters based on cadmium telluride II. The main achievements and current status (Review). Phys. Chem. Solid State. 13: 744-758.
  27. Das S, Bhowal M K and Dhar S, 2019. Calculation of the band structure, carrier effective mass, and the optical absorption properties of GaSbBi alloys. J. Appl. Phys. 125: 075705. doi:10.1063/1.5065573
  28. Moss T A, 1950. Relationship between the refractive index and the infra-red threshold of sensitivity for photoconductors. Proc. Phys. Soc. B. 63: 167−176. doi:10.1088/0370-1301/63/3/302
  29. Ravindra N M, Auluck S and Srivastava V K, 1979. On the Penn gap in semiconductors. Phys. Stat. Solidi (b). 93: K155−K160. doi:10.1002/pssb.2220930257
  30. Herve P J L and Vandamme L K J, 1995. Empirical temperature dependence of the refractive index of semi-conductors. J. Appl. Phys. 77: 5476−5477. doi:10.1063/1.359248
  31. Tripathy S K, 2015. Refractive indices of semiconductors from energy gaps. Opt. Mater. 46: 240−246. doi:10.1016/j.optmat.2015.04.026
  32. Anani M, Mathieu C, Lebid S, Amar Y, Chama Z and Abid H, 2008. Model for calculating the refractive index of a III-V semiconductor. Comput. Mat. Sci. 41: 570−575. doi:10.1016/j.commatsci.2007.05.023
  33. Reddy R R, Ram Gopal K, Narasimhulu K, Reddy L S S, Kumar K R, Balakrishnan G and Ravi Kumar M, 2009. Interrelationship between structural, optical, electronic and elastic properties of materials. J. Alloys Comp. 473: 28−35. doi:j.jallcom.2008.06.037
  34. Kushnir O S, Shchepanskyi P A, Stadnyk V Yo and Fedorchuk A O, 2019. Relationships among optical and structural characteristics of ABSO4 crystals. Opt. Mater. 95: 109221. doi:10.1016/j.optmat.2019.109221
(c) Ukrainian Journal of Physical Optics