Methods of obtaining of cds and cdse films and heterostructures on their basis. Review

Lviv Polytechnic National University
Lviv Polytechnic National University
Lviv Polytechnic National University
Lviv Polytechnic National University
Lviv Polytechnic National University

Alternative and renewable sources of energy, such as wind and solar energy, hydro and geothermal energy, are attracting increasing attention all over the world. The growing interest in them is caused by environmental considerations, on the one hand, and the limited traditional earth resources - on the other. A special place among them is occupied by photovoltaic converters of solar energy.

Semiconductor thin films of metal chalcogenides of zinc subgroups due to their unique optical and electrical properties can be used in photovoltaic systems. Cadmium chalcogenides films have become the most widely used. But due to the large number of factors that effects on the properties of films, which in turn significantly effects on the efficiency of photoconductors on their basis, the choice of simple, affordable and cheap method of film synthesis will help to avoid many of them and simplify work while developing new, or improvement of existing solar cells on their base. Improving of photoconductivity by increasing the short-circuit current in solar cells with a CdS or CdSe buffer layer requires reducing the optical absorption of photons with energies less than 2.4 eV, which can be achieved by minimizing of cadmium sulfide and cadmium selenide films thickness to the optimal size.

In this paper, the advantages and disadvantages of the main methods which are used to synthesize thin-film semiconductor materials are considered and thoroughly analyzed. The main attention is focused on the choice of the chemical surface deposition (CSD) method due to its simplicity in technological terms, possibility of using various and available material sources for the synthesis of a wide spectrum of semiconductor thin-film materials at the temperatures up to 100 °С on the substrates of different nature, shape and size with a minimum amount of waste.

The main synthesis conditions of cadmium chalcogenides films are analyzed, and the comparative characterization of their influence on optical and morphological properties of films are given. In the description of the CSD method the chemistry of the low soluble CdS compound formation process was described and the influence of the initial cadmium-containing salt, chalcogenizers, pH value and the substrate nature on the properties of CdS and CdSe films were considered. Synthesis conditions and properties of cadmium chalcogenides films, obtained by various methods, are summarized in one table.

Therefore, the search for an optimal method for the production of film materials is one of the key stages in the process of their synthesis with the required functional properties for the development of new thin-film semiconductor materials and the improvement of already developed materials on their base.

1. Gordillo G., Rojas F., Calderón C. (2003). Optical characterization of Cd (Sx, Te1-x) thin films deposited by evaporation. Superficies y Vacio. V. 16, № 3, 30-33.
2. Беляев А. П., Рубец В. П., & Калинкин И. П. (2003). Влияние резко неравновесных условий на стехиометрию состава слоя теллурида кадмия, конденсируемого из паровой фазы. Физика и техника полупроводников, Т. 37, Вып. 6, 641-643.
3. Майссел Л., Глэнг Р. (1977). Технология тонких пленок (справочник) / пер. с англ. под. ред. М. И. Елинсона, Г. Г. Смолко. М. Сов. радио Т.1.
4. Случинская И. А. (2002). Основы материаловедения и технологии полупроводников. Москва. Мифи.
5. Kumar V., Khan K. L. A., & Hussaine M. (2007). ZnSe sintered films: growth and characterization. Applied Surface Science, Vol. 25, № 3, Issue 7,35433546. doi. org/10.1016/j. apsusc.2006.07.066.
6. Pouzet J., Bernede J. C., & Benhida S. (1992). Preparation and characterization of tungsten diselenide thin films. Thin Solid Films, 208, 252-259. doi. org/10.1016/0040-6090(92)90652-R.
7. Mitzithra C., Hamilakis S., & Loizos Z. (2012). CdSe semiconducting layers produced by pulse electrolysis. Физика и техника полупроводников, Vol. 46 (5), 633-636. doi: 10.1134/S1063782612050168.
8. Sasikala G., Thilakan P., Subramanian C. (2000). Modification in the chemical bath deposition apparatus, growth and characterization of CdS semiconducting thin films for photovoltaic applications. Solar Energy Materials & Solar Cells, 62, 275-293. doi. org/10.1016/S0927-0248(99)00170-1.
9. Ravichandran K., Philominathan P. (2008). Investigations on microstructural and optical properties of CdS films fabricated by a low-cost, simplified spray technique using perfume atomizer for solar cell applications. Solar Energy, Vol. 82, 1062-1066. doi. org/10.1016/j. solener.2008.04.012.
10. Catalano A. (1996). Polycrystalline thin-film technologies: Status and prospects. Solar Energy Materials and Solar Cells, Vol.41-42, 205-217. doi. org/10.1016/0927-0248(95)00144-1.
11. Oladeji I. О., Chow L. (1997). Optimization of chemical bath deposited cadmium sulfide thin films. J. Electrochem. Soc, Vol. 144, No.7, 2342-2346. doi. org/10.1016/j. matlet.2017.05.117.
12. Ugai Ya. A., Semenov V. N., & Shamsheeva Y. L. (1988). Reactions between cadmium salts and thiourea in the preparation of cadmium sulfide films. Zh. Prikl. Khim. (Leningrad), no. 11, 2409-2414.
13. Палатник Л. С. (1978). Материаловедение в микроэлектронике. М.: Энергия.
14. Лякишев Н. П. (1996). Диаграммы состояния двойных металлических систем: справочник: в 3 т.: Т. 1 / под общ. ред. Н. П. Лякишева. М.: Машиностроение.
15. Susa K., Kobayashi T., Taniguchi S. (1980) High-pressure synthesis of rock-salt type Cd-S using metal sulfide additives. Journal of Solid State Chemistry, vol. 33(2), 197-202. doi. org/10.1016/00224596(80)90120-6.
16. Ohata K., Saraie J., Tanaka T. (1973). Phase diagram of the Cd-S - Cd-Te pseudobinary system. Japanese Journal of Applied Physics, vol. 12(8), 1198- 1204. doi: 10.1143/JJAP.12.1198.
17. Sowa H. (2005). On the mechanism of the pressure-induced wurtzite- to (NaCl)-type phase transition in Cd-S: an X-ray diffraction study. Solid State Sciences, vol. 7, 73-78. doi. org/10.1016/j. solidstatesciences.2004.10.011.
18. Mariano A. N., Warekois E. P. (1963) High pressure phases of some compounds of groups II-VI. Science, vol. 142, 672-673. doi: 10.1126/science.142.3593.672.
19. Kulakov M. P., Balyakina I. V., Kolesnikov N. N. (1989). Phase diagram and crystallization in the system Cd-Se - Zn-Se. Inorganic Materials, vol. 25(10), 1386-1389.
20. Sowa H. (2005). The high-pressure behaviuor of Cd-Se up to 3 GPa and the orientation relations between its wurtzite- and NaCl-type modifications. Solid State Sciences, vol. 7, 1384-1489. doi. org/10.1016/j. solidstatesciences.2005.09.003.
21. Холлэнд Л. (1963). Нанесение тонких пленок в вакууме / пер. с англ. Н. В. Васильченко. МоскваЛенинград: Госэнергоиздат.
22. Чопра К. Л. (1972). Электрические явления в тонких пленках / пер. с англ. [ под ред. Т. Д. Шермергора]. Москва: Мир.
23. Елинсон М. И., Смолко Г. Г. (1977). Технология тонких пленок: справочник: в 2 т.: М.: Мир.
24. Чопра К. (1986). Тонкопленочные солнечные элементы. Москва: Мир.
25. Gnatenko Yu. P., Bukivskij P. M., & Ivashchenko M. M. (2014). Photoluminescence of high optical quality CdSe thin films deposited by closespaced vacuum sublimation. Journal of Luminescence, Vol. 146, 174-177. doi. org/10.1016/j. jlumin.2013.09.070.
26. Lahewil A. S. Z., Al-Douri Y., & Ahmed N. M. (2013). Structural, analysis and optical studies of cadmium sulfide nanostructured. Procedia Engineering, vol. 53, 217-224. doi. org/10.1016/j. proeng.2013. 02.029.
27. Islam M. A., Hossain M. S., & Amin N. (2013). Comparison of structural and optical properties of CdS thin films grown by CSVT, CBD and Sputtering techniques. Energy Procedi, vol. 33, 203-213. doi. org/10.1016/j. egypro.2013.05.059.
28. Gopakumar N., Anjana P. S., Pillai P. K. V. (2010). Chemical bath deposition and characterization of CdSe thin films for optoelectronic applications. Journal of Materials Science, vol. 45, 6653-6656. doi: 10.1007/s10853-010-4756-1.
29. Старіков В. В., Іващенко М. М., & Перевертайло B. Л. (2009). Морфологія поверхні та оптичні властивості плівок CdSe отриманих методом квазізамкненого об'єму. Журнал нано- і електронної фізики, Т. 1, № 4, 100-109.