Quantum-Chemical Modeling of the Chemistry Process

Home , Tetrahydroxozincate, Zinc hydroxide

Chemistry, Technology and Application of Substances Vol. 3, No. 1, 2020

M. A. Sozanskyi, V. E. Stadnik, P. Yo. Shapoval, O. P. Kurylo, R. R. Guminilovych Lviv Polytechnic National University, Department of Physical, Analytical and General Chemistry [email protected]

QUANTUM-CHEMICAL MODELING OF THE CHEMISTRY PROCESS OF THE ZINC SULFIDE AND ZINC SELENIDE FILMS SYNTHESIS https://doi.org/ The quantum-chemical modeling of the synthesis process chemistry of ZnS and ZnSe in aqueos solutions was carried out.For modeling the simulation of ZnS synthesis was made through the formation of Zn(II) complex forms with the trisodium citrate, sodium hydroxide and the pair of ammonium hydroxide with hydrazine hydrate. For the synthesis of ZnSe was used only sodium hydroxide.It was established that this process passes through several intermediate stages with the transitional reactive complexes formation. On the basis of obtained data, the energy stages diagrams are constructed and the comparison of ZnS and ZnSe synthesis processes with various complexing agents is presented.The ZnS and ZnSe filmswere obtained by chemical synthesis method from an aqueous solution of zinc salt, complexing and chalcogenizing agents. X-ray phase analysis confirmed the formation of desired compounds, as well as the formation of ZnO in the case of ammonium hydroxide – hydrazine hydrate usage at the synthesis of ZnS films. Key words: zinc sulfide, zinc selenide, thin films, quantum-chemical modeling, semiempirical methods, semiconductors.

Introduction which occur between the liquid and solid phases Semi-empirical method of quantum chemistry (newly formed the reaction product and substrate) at is one of the modeling reactions methods between a short distance from the latter. molecules and substances by quantum-chemical cal- For the some metals ions (Me = Pb2+, Cu2+, culations [1–3]. In Refs. [4–6], the theoretical basis Cd2+, Hg2+), the formation of complexes with 2+ of metal sulfides films formation from aqueous thiourea of [Me((NH2)2CS)4] type was established solution were described. Among the main factors [4, 7]. From the reference data [4], the value of the affecting the course of the reaction, the following stability constant of such zinc complex is very small can be distinguished: (often absent in reference books),which does not 1. Concentration of initial reagents of the apply to the mentioned above metals. So it is logical solution from which depositionismade and the phy- to assume the formation of intermediate complexes sical parameters of the process (temperature, syn- of [Ln∙∙∙Zn∙∙∙(NH2)2CS] type, where zinc is coor- thesis duration, etc.); dinated on the one hand by ligands of the comp- 2. Nature of complexing and chalcogenizing lexing agent, and on the other by thiourea. The reagents that surround the metal ion and generate decomposition process of such intermediate comp- chalcogen ions during the synthesis, respectively; lexes, as a rule, involves the formation of molecular 3. Nature of the substrate surface on which the forms, and then monomolecular layers of zinc films are formed. chalcogenide. To reduce the formation of by-pro- It was noted [4] that during the synthesis ducts, it is necessary to create conditions in which process, the formation of transitional molecular the supply of zinc- and chalcogen-containing agents reactive complexes (TMRC), associates, cluster and will be the same. It is also worth noting that some colloidal forms were possible in the working solution complexing agents perform only one function – the due to cooperation and fluctuation phenomena, formation of a complex with metal. In this case, it is

1414 Quantum-chemical modeling of the chemistry process of the zinc sulfide and zinc selenide films synthesis necessary to add an additional pH regulator to ensure Results and discussion the stability and reactivity of the complex. Other The results of quantum chemical modeling of complexing agents are able tofulfill two functions at the ZnS and ZnSe films synthesis chemistry in the same time – to coordinate the metal ion and aqueous solutions with various complexing agents by create the required hydrogen index of the solution. semi-empirical methods are presented in table 1. The geometry of starting zinc complexes are illustratedin Aim of the work Fig. 1–3. The aims of the present study are the follo- Quantum-chemicalmodelingof ZnS synthesis wing: 1. Implementationofquantum-chemical mode- chemistry with Na3C6H5O7. ling of the ZnS and ZnSe synthesis processes Initially, when mixing solutions of zinc salt – withtheuseof PM7 method in MOPAC 2012 and trisodium citrate, a soluble [Zn(C6H5O7)] software package. This could be made on the basis of complex is formed (Fig. 1), where citrate ion plays the hypothesis about the possibility of formation of the role of a ligand. transient reactive complexes, associates, clusters, As can be seen from the conducted quantum- structures of colloidal nature, which are structural chemical modeling(table. 1, no. 1, stages 1–3) that units during the synthesis of zinc chalcogenide films after adding thiourea and a small amount of pH due to the effects of co-operation and fluctuation in regulator to the solution, the 3– the working solution. 2. Comparison of the obtained [(NH2)2CS∙∙∙Zn(OH)2(C6H5O7)] TMRC is formed results of ZnS and ZnSe simulations with the in the early stages of deposition. In the TMRC the investigated properties of respective films. 3. Feasi- Zn atom is coordinated with the S atom (Fig. 4). This bility and efficiency evaluation of the synthesis in process is accompanied by a slight endoeffect, that observed systems. is, energy absorption. Next, starting from stage 3 to stage 6, the Materials and research methods formed complex undergoes rearrangement of two Modeling and calculations of the system hydrogen atoms of (NH2)2CS with two hydroxyl energy change (ΔE) for the synthesis stages of zinc groups and detaching of two water molecules. As a 3– sulfide and zinc selenide were carried out by the result, [(N2H2СS∙∙∙Zn(C6H5O7)] TMRC is formed. semi-empirical method PM7 [8] with the use of The result of these stages is a decrease in total MOPAC 2012 software package [9] and the energy of the system. Winmostar graphical interface [10]. At the last stage, which is the most energy- The synthesis of ZnS films was carried out intensive, the newly formed intermediate complex from a working solution prepared by mixing aqueous decomposed with the formation of zinc sulfide, solutions of zinc chloride (ZnCl2), complexing agent, citrate ion and cyanamide (stages 6–7). thiourea ((NH ) CS) and, if necessary, the pH regu- 2 2 During deposition process, the citrate ion lator. Solutions of trisodium citrate (Na C H O ), 3 6 5 7 (C H O 3–) does not change its structure and sodium hydroxide (NaOH), and a pair of ammonium 6 5 7 performs only a ligand role. hydroxide (NH4OH) with hydrazine hydrate (N2H4·H2O) were used as complexing agents. The Quantum-chemicalmodelingof ZnS synthesis exact synthesis parameters of ZnS films are given in chemistry with NaOH. ref. [11]. In the case of mixing of a zinc salt solution The synthesis of ZnSe films was carried out with an excess of sodium hydroxide solution, which from a working solution prepared by mixing aqueous is a complexing agent and pH regulator at the same solutions of zinc chloride (ZnCl2), sodium hydroxide time, a soluble complex of tetratrahydroxozincate and elemental selenium (Se) dissolved therein with 2– ([Zn(OH)4] ) is formed (Fig. 2). the presence of hydrazine hydrate. The exact synthe- As can be seen from the performed modeling sis parameters of ZnS films are given in ref. [12, 13]. The X-ray diffraction patterns of deposited (table 1, no. 2, stages 1–2) that TMRC 2– ZnS and ZnSe films samples were performedwith the [(NH2)2CS∙∙∙Zn(OH)4] is formed at the beginning use of DRON-3.0 diffractometer (Cu Kα–radiation). of the deposition, after the addition of thiourea in the The primary treatment of films diffractogram for the working solution (Fig. 5). InthisTMRC, the zinc identification of phases was carried outby using atom is coordinated with the sulfur atom of the Powder Cell program [14]. thiourea, with a slight increase in system energy.

15 M. A. Sozanskyi, V. E. Stadnik, P. Yo. Shapoval, O. P. Kurylo, R. R. Guminilovych Table 1 Modeled stages of ZnS and ZnSe films synthesis and energy stages diagrams

Complexing No. Film Energy stages diagrams Modeled stages agent

-3000 Stages 1→3: ZnS (Na3C6H5O7) – – -3050 [Zn(C6H5O7)] + 2OH + (NH2)2CS → 3– → [(NH2)2CS∙∙∙Zn(OH)2(C6H5O7)] ; -3100 Stages 3→6: 3– 1. ZnS Na3C6H5O7 E, kJ/mol -3150 [(NH2)2CS∙∙∙Zn(OH)2(C6H5O7)] →  3– → [(N2H2СS∙∙∙∙∙Zn(C6H5O7)] + 2H2O ; -3200 Stages 6→7: 3– -3250 [(N2H2СS∙∙∙Zn(C6H5O7)] → ZnS↓ + 1 2 3 4 5 6 7 3– + C6H5O7 + CH2N2 . Stage number Stages 1→2: 2– -1550 [Zn(OH)4] + (NH2)2CS → 2– ZnS (NaOH) → [(NH2)2CS∙∙∙Zn(OH)4] ; -1600 Stages2→5: -1650 2– [(NH2)2CS∙∙∙Zn(OH)4] → 2– -1700 → [(N2H2СS∙∙ Zn(OH)2] + 2H2O ;

2. ZnS NaOH E, kJ/mol  -1750 Stages5→6: [(N H СS∙∙ Zn(OH) ]2– → -1800 2 2 2 2– [S∙∙∙Zn(OH)2] + CH2N2 ; -1850 1 2 3 4 5 6 7 Stages 6→7: Stage number 2– – [S∙∙∙Zn(OH)2] → ZnS↓ + 2OH .

Stages 1→2: -350 2+ – [Zn(NH3)4] + 2OH → Zn(OH)2 + ZnS (NH4OH + N2H4H2O) -400 4NH3↑; -450 Stages 2→3: Zn(OH)2 + (NH2)2CS → NH4OH + -500

3. ZnS E, kJ/mol → [(NH2)2CS∙∙∙Zn(OH)2] ; N2H4·H2O  -550 Stages 3→7: -600 [(NH2)2CS∙∙∙Zn(OH)2] → -650 → ZnS↓ + CH2N2 + 2H2O ; 1 2 3 4 5 6 7 Stage number By-process: Zn(OH)2→ZnO+ H2O .

-2300 ZnSe (NaOH) -2400 Stages 1→2: 2- 2- 4– [Zn(OH)4] + Se → [Se∙∙∙Zn(OH)4] ; -2500

4. ZnSe NaOH E, kJ/mol

 -2600 Stages 2→3: 4– – [Se∙∙∙Zn(OH)4] → ZnSe↓ + 4OH . -2700 1 2 3 Stage number

16 Quantum-chemical modeling of the chemistry process of the zinc sulfide and zinc selenide films synthesis

– 2– 2+ Fig. 1. The modeled [Zn(C6H5O7)] Fig. 2. The modeled [Zn(OH)4] Fig. 3. The modeled [Zn(NH3)4] complex complex complex

At the next stages 2-5, transition states occur As a consequence, the pH value decreases, which when the hydrogen atoms rearrange and transfer promotes the formation of zinc hydroxide. The from thiocarbamide to tetrahydroxozincate. As a decomposition of Zn(OH)2, during the passage of the result, two water molecules (stages 3–5) are detached main process, will probably lead to the appearance of 2– from the [(NH2)2CS∙∙∙Zn(OH)4] TMRC with the the zinc oxide (ZnO) phase as a by-product of the 2– appearance of a new [(N2H2СS∙∙∙Zn(OH)2] TMRC. reaction. This may have happen at conditions, given The outcome of these stages is a decrease in the total in ref. [11]. The two water molecules are detach energy of the system. from Zn(OH)2 and it transforms to ZnO (table 1, Further (stages 5–6), this intermediate comp- no. 3,by-process). lex decomposed with the formation of cyanamide In the subsequent stages, thiourea is combined and an intermediate phase – zinc dihydroxosulfide with the newly formed Zn(OH)2 (stages 2-3). This 2– [S∙∙∙Zn(OH)2] , which is also accompanied by a produces the [(NH2)2CS∙∙∙Zn(OH)2] TMRC (Fig. 6). decrease in the total energy of system. After that, during the further heating 2– At the last stages 6–7, [S∙∙∙Zn(OH)2] (stages 3–7) the intermediate complex undergoes to decomposes into insoluble zinc sulfide and two rearrangement of hydrogen atoms with detaching of hydroxyl groups, and the stages themselves are the water molecules and destruction into cyanamide most energy-intensive. molecules and insoluble ZnS. Going to the last stage Quantum-chemicalmodelingof ZnS synthesis leads to a decrease in the total energy of the system, chemistry with NH4OHandN2H4·H2O. however, in the process of passing through the Zinc can form with complexing agents of stages 3–7 there are local minimum and maximum of NH4OH and N2H4·H2O the water-soluble complexes ΔE energy change. 2+ of zinc tetraammonia [Zn(NH3)4] and zinc Quantum-chemicalmodelingof ZnSe synthesis 2+ tetrahydrazine [Zn(N2H4)4] , respectively. chemistry with NaOH. Since, according to reference data [15], the Similarly to the synthesis of ZnS from a value of stability constant for the zinc complex with NaOH solution, in the case of ZnSe formation from ammonia (pK1–4 = 9.08) is almost five orders higher hydroxide system, a soluble tetrahydroxy zincate 1–4 2– than with hydrazine (pK = 3.84), thenthe [Zn(OH)4] complex will form. Itsgeometry 2+ [Zn(NH3)4] complex form (Fig. 3) will be present in areillustrated inFig. 3. The difference in this process the working solution. will be the different nature of the chalcogenizing It can be seen from the modeling (table 1, reagent, namely the generated Se2– ions from no. 3, stages 1–2) that ZnS deposition is preceded by elemental powdered selenium. the stage of nucleation of the zinc hydroxide The results of quantum chemical modeling (Zn(OH)2) phase. (table 1, no. 4, stages 1–2) indicate that at the With increasing system energy, the complex beginning of the deposition, selenium ion is 2+ [Zn(NH3)4] decomposes to Zn(OH)2 and the coordinated with the zinc atom of tetrahydroxy 4 ammonia as volatile compound evaporates from the zincate forming the [Se∙∙∙Zn(OH)4] TMRC (Fig. 7). working solution. This reduces the NH4OH This process requires the supply of energy to the concentration during the process of ZnS synthesis. system.

17 M. A. Sozanskyi, V. E. Stadnik, P. Yo. Shapoval, O. P. Kurylo, R. R. Guminilovych

Fig. 4. The modeled Fig. 5. The modeled 3– 2– [(NH2)2CS···Zn(OH)2(C6H5O7)] TMRC [(NH2)2CS···Zn(OH)4] TMRC

4– Fig. 6. The modeled [(NH2)2CS···Zn(OH)2]TMRC Fig. 7. The modeled ПРЗК[Se···Zn(OH)4] TMRC

Upon further heating of the reaction mixture According to quantum calculations (table 1), (steps 2-3), the intermediate complex decomposed in all cases of ZnS and ZnSe synthesis, it is with the formation of insoluble zinc selenide and necessary to provide energy to start the initial stages four hydroxide groups. and pass the energy barrier (the plot that connects the It is worth noting that in the case of obtaining first two points on the energy diagrams). It reaches the results of quantum-chemical calculations by the the highest value for ZnS synthesis with the use of semiempirical PM7 method, their accuracy for the NH4OH and N2H4·H2O complexing agents ZnSe formation process decreases, unlike for ZnS (197 kJ/mol). It is somewhat smaller for the ZnSe films, since the quantitative content of lighter atoms synthesis (105.6 kJ/mol) and the smallest for ZnS

(H, C, O, N, S) in the modeled system decreases and synthesis with the use of NaOH and Na3C6H5O7 the heavier ones (Zn, Se) grows. This increases the (31.8 and 27.2 kJ/mol, respectively). number of approximations performed in the calcu- To verify the results of quantum-chemical lations by semiempirical method [16]. modeling of ZnS and ZnSe obtaining, the ZnS and

18 Quantum-chemical modeling of the chemistry process of the zinc sulfide and zinc selenide films synthesis ZnSe films were synthesized experimentally under formation, the NaOH complexing agent behaves modeled conditions. Their X-ray phase analysis was energetically more profitably during the ZnS syn- performed (figs. 8, 9). It has been established that thesis in the aggregate of all stages of synthesis coatings contain the corresponding phases of cubic reactions. However, according to the studies (sphalerite-type) modification. In all cases, the films described in [17], it was established that when NaOH were single-phase, except for the ZnS films synthesis was used, the surface of the synthesized films with the use of ammonium hydroxide with hydrazine consisted of spherical particles. Their contact area hydrate. Such samples containedtwo phases ZnO and with the substrate surface is small.This results in ZnS, which was predicted by modeling ofthecor- weak adhesion to glass substrates and the ZnS layer responding case. could be removed by applying mechanical forces to the coating. Also, during prolonged synthesis, the upper film layer of ZnS spherical particles was

- ZnS (theoretical) partially washed out at cleaning of its surface by a jet - ZnO (theoretical) of distilled water. The ZnS formation reaction with the use of

(3) Na3C6H5O7 complexing agent is less energy profi- table. However, the obtained ZnS coatings were characterized by a solid, smooth and mirror surface

Intensity (2) with good adhesion to glass substrates [11, 18]. With the increase in deposition duration, there was observed a linear region of increase in the films (1) thickness with uniform growth over the entire substrate surface. The formation of spherical particles 30 40 50 60 70 80 90 was not found, but only a small amount of surface 2 degrees defects. The ZnS contact area with the substrate is Fig. 8. The XRD patterns of ZnS films, large, which explains the good adhesion. After obtained with the use of Na С Н O (1), NaOH (2), 3 6 5 7 depletion of the working solution, the number of NH4OH+N2H4·H2O (3) and thetheoretical diffraction patterns of ZnS і ZnO conglomerates on the film surface increases and it begins cracking.

In the case of the use of NH4OH and ZnSe (theoretical) N2H4·H2O complexing agents,the zinc sulfide synthesis characterized by a tendency to form by- products [11, 19] and the deposition process itself is more energy-intensive than with the other

Intensity complexing agents. This makes it impossible to use

NH4OH and N2H4·H2O for the production of film elements based on ZnS and ZnSe. The obtained sulfide films under similar conditions with another element of the zinc subgroup – cadmium did notcon- 20 30 40 50 60 70 80 tain by-products [20, 21]. 2 degrees The ZnSe synthesis requiresmore energy for it Fig. 9. The XRD pattern of ZnSe film, formation than the synthesis of ZnS. This can be obtained with the use of NaOH the theoretical explained by a different nature of the chalcogenizing diffraction patterns of ZnSe agent, which was used to obtain zinc selenide (Se2- Conclusions ions are negatively charged instead of electroneutral From the performed simulations and cal- (NH2)2CS). As a consequence, there is a need to culations for the four cases of zinc chalcogenides overcome the repulsion between Se2– and OH– ions.

19 M. A. Sozanskyi, V. E. Stadnik, P. Yo. Shapoval, O. P. Kurylo, R. R. Guminilovych The synthesis of ZnS films was performed 11. Shapoval, P., Sozanskyi, M., Yatchyshyn, I., Kulyk, with the use of trisodium citrate, sodium hydroxide B., Shpotyuk, M., & Gladyshevskii, R. (2016). The Effect of and a pair of ammonium hydroxide – hydrazine Different Complexing Agents on the Properties of Zinc Sulfide Thin Films Deposited from Aqueous hydrate. For the ZnSe films synthesis only sodium Solutions. Chemistry & Chemical Technology, 10(3), 317– hydroxide was used. The X-ray analysis confirmed 323. doi: 10.23939/chcht10.03.317 the ZnS formation, as well as the ZnO formation 12. Sozans’kyy, M., Shapoval, P., Chaykivs’ka, R., duringthe synthesis of ZnS films withthe useof Stadnik, V., & Yatchyshyn, Y. (2016). Hidrokhimichnyy syntez tonkykh plivok tsynku selenidu (ZnSe) v NH4OH and N2H4·H2O, which was predicted by the prysutnosti natriyu hidroksydu ta yikhni vlastyvosti. correspondingquantum-chemical modeling. Visnyk Natsional’noho universytetu “L’vivs’ka politekhnika”. Seriya: Khimiya, tekhnolohiya rechovyn ta References yikh zastosuvannya, 841, 36–42. 1. Thiel, W. (2014). Semiempirical quantum-chemical 13. Sozanskyi, M., Chaykivska, R., Shapoval, P., methods. WIREs Computational Molecular Science, 4(2), Yatchyshyn, I., &Vytrykush, N. (2018). Influence of 145–157. doi:10.1002/wcms.1161 deposition duration on properties of ZnSe and ZnSxSe1-x 2. Bertoli, A. C., Carvalho, R., Freitas, M. P., films. Visnyk of the Lviv University. Series Ramalho, T. C., Mancini, D. T., Oliveira, M. C., Varennes Chemistry, 59(1), 131. doi: 10.30970/vch.5901.131 A., & Dias, A. (2015). Theoretical and experimental 14. Kraus, W., & Nolze, G. (1996). POWDER CELL investigation of complex structures citrate of zinc – a program for the representation and manipulation of (II). Inorganica Chimica Acta, 425, 164–168. doi: crystal structures and calculation of the resulting X-ray 10.1016/j.ica.2014.10.025 powder patterns. Journal of Applied Crystallography, 3. Bertoli, A. C., Carvalho, R., Freitas, M. P., 29(3), 301–303. doi:10.1107/s0021889895014920 Ramalho, T. C., Mancini, D. T., Oliveira, M. C., Varennes 15. Lur’ê, YU. YU. (1989). Spravochnik po A., & Dias, A. (2015). Theoretical spectroscopic studies analiticheskoy khimii. Moskva: Khimiya. and identification of metal-citrate (Cd and Pb) complexes 16. Accuracy of PM7. (2012). Retrieved from by ESI-MS in aqueous solution. Spectrochimica Acta Part http://openmopac.net/PM7_accuracy/PM7_accuracy.html A: Molecular and Biomolecular Spectroscopy, 137, 271– 17. Shapoval, P., Sozans’kyy, M., & Yatchyshyn, Y. 280. doi: 10.1016/j.saa.2014.08.053 (2015). Syntez I vlastyvosti plivok tsynksul’fidu (ZnS), 4. Markov, V., Maskayeva, L., & Ivanov, P. (2006). otrymanykh z vykorystannyam kompleksoutvoryuvacha Gidrokhimicheskoye osazhdeniye plenok sul’fidov natriyhidroksydu. Visnyk Natsional’noho Universytetu metallov: modelirovaniye i yeksperiment. Yekaterinburg: “L’vivs’ka Politekhnika”. Seriya: Khimiya, tekhnolohiya UrO RAN. rechovyn ta yikh zastosuvannya, 812, 43–47. 5. Berg, L., Meshchenko, K., & Bogomolov, YU. (1970). 18. Sozanskyi, M., Shapoval, P., Yatchyshyn, I., Vybor optimal’nykh usloviy osazhdeniya plenok sul’fida svintsa. Neorganicheskiye materialy, 6(7), 1337–1338. Stadnik, V., & Gladyshevskii, R. (2015). Synthesis of ZnS 6. Markov, V, & Maskayeva, L. (2005). Raschet uslo- thin films from aqueous caustic of trisodium citrate and viy obrazovaniya tverdoy fazy khal’kogenidov metallov their properties. Odes’Kyi Politechnichnyi Universytet. pri gidrokhimicheskom osazhdenii. Yekaterinburg: GOU Pratsi, (3), 71–75. doi: 10.15276/opu.3.47.2015.17 VPO UGTU−UPI. 19. Shapoval, P., Sozans’kyy, M., Yatchyshyn, Y. & 7. Jalilehvand, F., Amini, Z., & Parmar, K. (2012). Huminilovych R. (2014). Syntez plivok tsynk sul’fidu Cadmium(II) Complex Formation with Selenourea and (ZnS) metodom khimichnoho poverkhnevoho osadzhen- Thiourea in Solution: An XAS and 113Cd NMR Study. nya. Visnyk Natsional’noho universytetu “L’vivs’ka Inorganic Chemistry, 51(20), 10619–10630. politekhnika”. Seriya: Khimiya, tekhnolohiya rechovyn ta doi:10.1021/ic300852t yikh zastosuvannya, 787, 31–35. 8. Bochkarev, V., Soroka, L., Klimova, T., & Veliko- 20. Lo, Y., Choubey, R., Yu, W., Hsu, W., & Lan, C. rechina, L. (2015). Modeling of Condensation Reaction of (2011). Shallow bath chemical deposition of CdS thin Aniline to Diphenylamine by PM7 Method. Procedia film. Thin Solid Films, 520(1), 217–223. doi: Chemistry, 15, 320–325. doi:10.1016/j.proche.2015.10.051 9. Stewart, J. (2012). MOPAC2012 Home Page. 10.1016/j.tsf.2011.07.035 Retrieved from http://openmopac.net/MOPAC2012.html 21. Reddy, M. (2013). Properties of CdS Chemically 10. Senda, N. (2018). Winmostar – Structure modeler Deposited thin films on the Effect of Ammonia and visualizer for free Chemistry simulations. Retrieved Concentration. IOSR Journal of Applied Physics, 4(4), from https://winmostar.com/ 01–07. doi: 10.9790/4861-0440107

20 Quantum-chemical modeling of the chemistry process of the zinc sulfide and zinc selenide films synthesis

М. А. Созанський, В. Є. Стаднік, П. Й. Шаповал, О. П. Курило, Р. Р. Гумінілович Національний університет “Львівськаполітехніка”, кафедра фізичної, аналітичної та загальної хімії

КВАНТОВО-ХІМІЧНЕ МОДЕЛЮВАННЯ ХІМІЗМУ ПРОЦЕСУ СИНТЕЗУ ПЛІВОК ЦИНКУ СУЛЬФІДУ ТА ЦИНКУ СЕЛЕНІДУ

Проведено квантово-хімічне моделювання процесу синтезу ZnS та ZnSe у водних розчинах. Змодельовано синтез ZnS утворенням проміжних комплексних форм Zn(II) з тринатрій цитратом, натрій гідроксидом та парою амоній гідроксиду з гідразин гідратом. Під час синтезу ZnSe використано лише натрій гідроксид. Встановлено, що цей процес проходить через декілька проміжних стадій з утворенням перехідних реакційноздатних комплексів. На основі отриманих даних побудовано енергетичні діаграми стадій та здійснено порівняння процесів синтезу ZnS і ZnSe з різними комплексоутворювальними реагентами. Методом хімічного синтезу отримано плівки ZnS та ZnSe з водного розчину солі цинку, комплексоутворювального та халькогенізуючого реагентів. Рентгенофазовим аналізом підтверджено утворення цільових сполук, а також формування ZnO під час синтеуі плівок ZnS з використанням амоній гідроксиду і гідразин гідрату. Ключові слова: цинк сульфід, цинк селенід, тонкі плівки, квантово-хімічне моделювання, напівемпіричні методи, напівпровідники.