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ФИЗИЧЕСКОЕ МАТЕРИАЛОВЕДЕНИЕ
DOI: 10.5862/JPM.237.3 UDC: 539.216
Y.S. Sakhare', N.R. Thakare', A.U. Ubale2
' P.R. Pote College of Engineering & Management, Amravati, India
2 Government Vidarbha Institute of Science and Humanities, Amravati, India
INFLUENCE OF QUANTITY OF SPRAY SOLUTION ON THE PHYSICAL PROPERTIES OF SPRAY DEPOSITED NANOCRYSTALLINE MgSe THIN FILMS
Nanocrystalline MgSe thin films have been prepared by varying the quantity of spray solution using the spray pyrolysis technique. The effect of the varying quantity of spray solution on the structural, electrical, morphological and optical properties of MgSe thin films was investigated. The X-ray diffraction studies revealed that the deposited MgSe has a cubic lattice with (111) as the preferred orientation. The optical studies showed that the deposited MgSe exhibited direct optical band gap which varied from 2.45 to 2.75 eV depending on the quantity of spray solution. The electrical resistivity of MgSe decreased with an increase in temperature indicating its semiconducting nature. The electrical resistivity, activation energy and optical band gap energy were found to depend upon the quantity of spray solution. The measurement of thermo-emf with applied temperature gradient across the film confirmed its ^-type conductivity.
THIN FILMS, X-RAY DIFFRACTION, OPTICAL PROPERTIES.
1. Introduction
The alkaline earth chalcogenides such as MgSe, CaSe, SrSe, etc., have attracted the scientific community due to their potential applications in various optoelectronic devices, especially luminescent ones. M.W. Wang, et al. [1] have studied the growth of MgSe films of zinc-blende structure on ZnTe substrates by the molecular beam epitaxy (MBE) method. The surface reconstructions of MgSe under different flux ratios and growth temperatures were studied. A.L. Rouff, et al. [2] have studied MgSe using the energy dispersive X-ray diffraction to 202 GPa and local density approximation to ultra-soft pseudo-potentials to 500 GPa. It was reported that MgSe underwent continuous phase transformation from rocksalt to FeSi. P. Prete, et al. [3]
have reported growth and characterization of ZnMgSe and MgSe on (100) GaAs by low-pressure metallorganic vapour phase epitaxy (MOVPE). The crystallographic phases of as grown MgSe and ZnMgSe were investigated. F.A. Sahraoui, et al. [4] have reported the structural and electric properties of MgSe at high hydrostatic pressure by the pseudopotential plane wave method. R. Pendey, et al. [5] have studied structural phase transition on MgSe from wurtzite zinc-blende to rocksalt phase by the periodic Hartree-Fock method. As compared to low pressure, the MOVPE and MBE methods used for the deposition of MgSe thin films, the spray pyrolysis method has many advantages, such as high deposition rate, control of various deposition parameters and low cost [6 — 12]. The spray method has been used for several decades in glass industry and
in solar cell production to deposit electrically conducting electrodes. Thin film formation using this technique involves spraying a metal salt solution onto a heated substrate. The sprayed droplet reaching the hot substrate surface undergoes spyrolytic decomposition and forms the desired product. The other volatile by-products escape in the vapour phase. The quality and properties of the films depend largely on substrate temperature, precursor solution concentration, spray rate and substrate, etc. Previous studies have shown that very few reports are available on growth of MgSe films by solution growth [13, 14] by the metalorganic vapour chemical deposition (MOVCD) [5] and MBE [1] methods. The effect of triethanolamine (TEA) on the physical properties of MgSe thin films grown by the chemical bath deposition method has been reported in our earliear report [15]. The purpose of this work is to investigate the effect of the quantity of spray solution on the physical properties of MgSe thin films. This paper reports structural, electrical and optical properties of MgSe thin films prepared by varying the quantity of the spray solution from 5 to 30 ml.
2. Deposition of MgSe thin films
MgSe thin solid films were prepared using the versatile spray pyrolysis technique, which is simple and economic as compared to the MBE and MOCVD methods. The properties of the film can be controlled by adjusting the preparative parameters such as substrate temperature, spray rate, quantity of spray solution, pH of spray solution, etc. Aqueous solutions of magnesium chloride (MgCl2), selenium oxide (SeO2) and triethanolamine NH (CH2-CH2)3 (TEA) were prepared using double distilled water. The glass substrates were ultrasonically cleaned and purged with acetone prior to the deposition. The spray solution was prepared by mixing 10 ml of 0.12 M MgCl2, 10 ml of 0.10 M TEA and 10 ml of 0.13 M SeO2. The MgSe thin films of various thicknesses were deposited by spraying 5, 10, 15, 20, 25 and 30 ml of spray solution onto preheated amorphous glass substrates, maintained at a temperature of 523 K. The spray rate was kept at 4 ml/min. The distance of 25 cm was kept between the substrate and the nozzle. The
MgSe film thickness was measured using weight difference method (by sensitive microbalance for thin films) and considering bulk density of MgSe.
The X-ray diffractogram was recorded using PANalytical X'Pert PRO MRD diffractometer with Cu^T line in 20 range from 20 to 90°. The compositional analysis of the deposited film was carried out by Energy Dispersive X-ray Spectroscopy and microstructure aspects of the films were studied with a JOEL'S JSM-7600F Scanning Electron Microscope with the resolution of 1 nm and an Atomic Force Microscope (AFM) from Park Scientific Instruments. The optical absorption spectrum was recorded using the JASCO V-530 UV/ Visible Spectrophotometer at normal incidence in the wavelength range from 300 to 900 nm. The electrical resistivity of the film was measured in the temperature range from 300 to 550 K by employing the two point probe method; quick drying silver paste was used as a contact material. A chromel-alumel thermocouple was used to measure the temperature of the sample. The type of electrical conductivity of the films was determined from the sign of the thermo-emf developed across the hot and cold junction.
3. Results and discussion
Film formation mechanism. The aqueous solution containing Mg2+ ions complexed with TEA, i.e. [Mg (TEA)] 2+ along with SeO2, was sprayed onto hot substrates kept at a temperature of 523 K. The sprayed droplets underwent thermal decomposition and well-adherent milk-white colored MgSe thin films were deposited. The film formation takes place according to the following reaction:
SeO2 + H2O ^ H2SeO3;
[Mg(TEA)]2+ + H2SeO3 +
(1)
+ 4 Cl - ^(523 K) ^ MgSej + (2) + TEA + HCl î + 2O2î.
The deposited films were uniform, pinholefree and adherent to the glass substrate. Fig. 1 shows the variation of film thickness as a function of the quantity of spray solution. The film thickness is 145 nm for a 5 ml spray solution and it increases to 188 nm as the spray
140
4 9 14 19 24 29
Volume of spray solution, ml
Fig. l.The plots of MgSe film thickness versus the volume of the spray solution
solution becomes 10 ml. However, a slight decrease in the film thickness was observed with a further increase in the quantity of the spray solution. This may be due to incomplete thermal decomposition of the spray solution. Here, the optimum quantity of the spray solution was found to be 10 ml and above it the film surface started becoming somewhat powdery, giving lower thickness [16].
Structural studies. The grown films were
characterized by X-ray diffraction (XRD) using Cu^ radiation, for structural identification and
a '
changes in the crystallinity of MgSe. Fig. 2 shows XRD patterns of MgSe films deposited by varying the quantity of the spray solution.
The films are nanocrystalline in nature with cubic lattice (see Table). The XRD pattern exhibits the major (111) orientation which becomes prominent with an increase in the thickness. Beside this, other diffraction peaks
H H -1
—-_J g f о ГМ ГМ 6
UL 1 5 о о _L ._
1 1 4
— J 'v. 3 — i
_J_ Л 2 Л
------J A _ 1
20 30 40 50 60 70 SO 90
Fig. 2. X-ray diffraction patterns of MgSe thin films deposited changing the spray solution volume, ml: 5 (7), 10 (2), 15 (3), 20 (4), 25 (5), 30 (6)
Table
The obtained physical properties of MgSe thin films depending on the spray solution volume
Spray solution Film Band gap Activation Grain size, p x102, Q-cm,
volume, ml thickness, nm energy, eV energy, eV nm at 373 K
05 145 2.75 0.97 11 23
10 188 2.45 0.86 24 11
15 184 2.50 0.87 21 13
20 179 2.60 0.88 17 14
25 168 2.65 0.90 13 07
30 157 2.69 0.92 10 20
Fig. 3. Scanning electron microscopy images of MgSe thin films deposited by changing the spray solution volume, ml: 05 (a), 10 (b), 15 (c), 20 (d), 25 (e), 30 (f
of (200), (220) and (400) are observed. These patterns clearly demonstrate that the film thickness of 188 nm deposited by spraying 10 ml of the solution is more oriented than others. The variation in the peak intensity with respect to the quantity of the spray solution may also be attributed to the variation in the film thickness and the grain structure. The average crystallite size of the deposited material was determined using Debye-Scherer's formula:
d = 0.9V(Pcos6),
(3)
where p is the peak width at half-height (in radians), 1 is the wavelength of Cu^T radiation
(1 = 1.5418 A), 0 is Bragg's diffraction angle at peak position (in degrees).
The average crystallite size was found to vary between 10 to 24 nm as the film thickness was changed from 145 to 188 nm (see Table). Above 10 ml of the spray solution, the film thickness and the grain size gradually decrease due to the formation of powdery film. Consequently, the thicker films consist of larger grains as compared to the thinner ones.
Surface morphology. Fig. 3 shows scanning electron microscopy (SEM) micrographs of spray-deposited MgSe thin films. The SEM micrograph reveals that the substrates were
Energy, keV
Fig. 4. Typical energy dispersive X-ray analysis spectrum of MgSe thin film of thickness 188 nm
(the volume of the spray solution is 10 ml)
Fig. 5. AFM images of MgSe thin films deposited by changing the volume of the spray
solution: 5 ml (a) and10 ml (b)
well-covered with a uniform distribution of a large number of fine grains. As the quantity of spray solution increased from 5 to 10 ml, a remarkable grain growth is observed. The film deposited using 10 ml spray solution has well-defined MgSe nano-rods along with spherical grains showing spikes on the surface. However, this type of morphology is suppressed as the quantity of the spray solution is increased above 10 ml. This fact confirms that films deposited with the optimum quantity of the spray solution, i.e., 10 ml, are more useful due to their porous nature.
A typical energy dispersive X-ray analysis (EDAX) spectrum of MgSe thin film deposited using the spray solution of the volume ranging from 5 to 30 ml is shown in Fig. 4. The formation of MgSe is confirmed from the elemental analysis. Other peaks appearing due to glass substrate can also be observed.
Fig. 5 shows an atomic force microscopy (AFM) image of MgSe films deposited with 05 and 10 ml of the spray solution. It is evident that the film surface is uniform and homogenous.
Optical properties. The optical absorption spectra of the films of different thicknesses were recorded and analyzed to estimate band gap energies of MgSe. The variation in
absorption density at with a wavelength 1 for all the samples is shown in Fig. 6. It is evident that the absorption coefficient of the MgSe film is of the order of 104 cm-1.
To confirm the nature of the optical transition in these samples, the optical data was analyzed using the classical relationship [17]:
ahv = A(Eg - hv)n, (4)
where a is the absorption coefficient, A is the constant, h is the Planck constant, v is the photon frequency, Eg is the optical band-gap energy, and n is 1/2 and 2 for the direct and the indirect transition, respectively.
Fig. 7 shows the variation of (ahv) 2 values versus hv values for MgSe thin films of various thicknesses. The extrapolation of the straight-line portion of the plot to zero absorption coefficient gives the value of the band gap energy E.
Fig. 8 shows the changing of the optical band-gap energy of the MgSe thin film with the volume of the spray solution. The energy gap increases from 2.45 to 2.75 eV as the film thickness decreases from 188 to 145 nm [18, 19]. The red shift observed in the absorption edge of MgSe thin film results from the smaller grain size of the nanostructured material as the
Wavelength X, nm
Fig. 6. Plots of the optical absorption at versus wavelength X for MgSe thin films deposited by changing the quantity of the spray solution (see Table)
hv, eV
Fig. 7. Plots of (ahv)2 values versus hv values for MgSe films. Volumes of spray solution are given in Table
Fig. 8. The dependence of the optical band gap energy of the MgSe film on the volume of the spray solution
quantum size effect becomes prominent [20].
Electrical properties. The d.c. electrical resistivity of all the deposited samples was studied in the temperature range from 300 to 500 K using the two-probe method. The variation of the log p value with the reciprocal of temperature (1000/J) is shown in Fig. 9. The electrical resistivity follows the relation
p = p0 exp(-£ /(kJ)), (5)
where p is the resistivity at temperature J, p0 is
the constant, k is the Boltzmann constant, E is
' ' a
the activation energy required for conduction.
The electrical resistivity of thinner film was found to be 2.3* 103 H-cm and it decreases to 1.1 * 103 H-cm as film thickness becomes 188 nm. The improvement in crystallinity and the grain size with thickness induces conductivity. Fig. 10 shows the dependence of electrical resistivity on the volume of the spray solution for the MgSe thin film. For all the samples it was obtained that the electrical resistivity decreases
Log (р) 1.4 1.3 1.2 1.1 1.0 0.9
1.8
* 145 nrti -а- 188 nm -*— 184 nm х -179 nm
-*— 168 nm *-157nm
___. _ —
/г"
* **«
„ л » » В -Я
-=8-В-—B-
2.0 2.2 2.4 2.6 2.8 3.0 3.2
103/Г, K-
Fig. 9. The plots of Log (p) value versus (103/7) for MgSe thin films deposited varying the quantity of the spray solution (see Table)
Fig. 10. The dependence of the resistivity of MgSe thin films obtained at 373 K on the volume of the spray solution
with an increase in temperature, confirming the semiconducting nature of MgSe. The thermal activation energies were calculated and were found to vary from 0.97 to 0.87 eV depending on the film thickness (Fig. 11).This variation in the activation energy with the film thickness is due to the changes in the crystalline structure and the density of dislocations in the film.
Thermo-emf measurement. The temperature difference applied across the film causes the transport of carriers from the hot end to the cold one thus creating an electric field. It was concluded from the polarity of the thermoelectric-emf that MgSe film exhibited ^-type conductivity. Fig. 12 shows the variation of thermo-emf with applied temperature difference.
9 14 19 24
Volume of spray solution, ml
Fig. 11. The dependence of the activation energy of MgSe thin films on the volume of the spray solution
0.83
% 0.63
a
и
tD
£ 0.43
0.23
—145 nm A
- 188nm M
* 184 ran Ж
» 179 nm
— 168 nm
—•— 157 nm
f .' " " 1 1 ' 1
25
55
85 115 145
Temperature difference, K
175
205
Fig. 12. The plots of thermo e.m.f. versus temperature differences applied across the MgSe thin films
It is evident that the thermo-emf increases linearly with the applied temperature difference. The thermo-emf developed across the film increases with thickness, which may be due to the improvement in the crystalline structure of the film [21]. At lower thickness the grain boundary
scattering is prominent which may decrease with thickness due to the grain growth.
4. Conclusions
Magnesium selenide thin films of thickness from 145 to 188 nm were deposited onto glass
substrates at 523 K using the spray pyrolysis technique with varying the quantity of the spray solution. The grown films are nanocrystalline in nature with cubic structure. The crystallinity and the grain size of MgSe is improved with thickness. The films deposited by spraying 10 ml of the solution are porous, showing growth
of nano-rods. The optical band-gap energy decreases with an increase in film thickness. It is, therefore, concluded that the physical properties of the magnesium selenide films can be customized by merely controlling the film thickness, which in turn becomes suitable for a particular application.
REFERENCES
[1] M.W. Wang, M.C. Phillips, J.F. Swenberg,
et al., «-CdSe/p-ZnTe based wide band-gap light emitters: Numerical simulation and design, J. Appl. Phys. 73 (1993) 4660.
[2] A.L. Rouff, T. Li, A.C. Ho, et al., Sevenfold coordinated MgSe: Experimental internal atom position determination to 146 GPa. Diffraction studies to 202 GPa, and theoretical studies to 500 GPa, Phys. Rev. Lett. 81 (1998) 2723.
[3] P. Prete, N. Lovergine, L. Tapfer, et al., MOVPE growth of MgSe and ZnMgSe on (100) GaAs, J.Cryst. Growth, 214 (2000) 119.
[4] F.A. Sahraoui, F. Arab, S. Zerroug, L. Louail, First-principles study of structural and elastic properties of MgSe under hydrostatic pressure, Comp. Mater. Sci. 41 (2008) 538.
[5] R. Pandey, A. Sntijianto, Study of structural phase transition in MgSe, Solid State Commun. 91 (1994) 269.
[6] A.U. Ubale, Y.S. Sakhare, Growth of nanocrystalline MgSe thin films by spray pyrolysis, Vacuum 99 (2014) 124.
[7] Y. Takemura, H. Suto, N. Honda, et al., Characterization of FeSe thin films prepared on GaAs substrate by selenization technique, J. Appl. Phys. 81 (1997) 5177.
[8] C.E.M. Campos, J.L. de Lima, T.A. Grandi, et al., GaSe formation by mechanical alloying Ga50Se50 mixture, Solid State Commun. 23 (2003) 179.
[9] B. Ouertani, J. Ouertfelli, M. Saadoun, et al., Transformation of amorphous iron oxide films pre-deposited by spray pyrolysis into FeS2-pyrite films, Mater. Lett. 59 (2005) 734. 2
[10] A.U. Ubale, Y.S. Sakhare, M.R. Belkhedkar, Synthesis and characterization of spray deposited nanostructured FeSe thin films, Mater. Lett. 92 (2013) 111.
[11] B. Ouertani, J. Ouertfclli, M. Saadoun, et al., Transformation of amorphous iron oxide thin films predeposited by spray pyrolysis into a single FeSe2-phase by selenisation, Sol. Energy Mater. Sol. (Cells. 87 (2005) 501.
[12] X.J. Wu, Z.Z. Zhang, J.Y. Zhang, et al., Structural and electrical characterizations of single
tetragonal FeSe on Si substrate, J. Cryst. Growth. 300 (2007) 483.
[13] A.U. Ubale, Y.S. Sakhare, Thickness dependent physical properties of chemically deposited nanocrystalline MgSe thin films deposited at room temperature by solution growth method, Mater. Sci. Semi. Processing. 16 (2013) 1769.
[14] A.U. Ubale, Y.S. Sakhare, Physical properties of MgSe thin films grown by chemical bath deposition method: effect of molar concentration of MgCl2, Ind. J. Phys. 87(12) (2013) 1183.
[15] A.U. Ubale, Y.S. Sakhare, S.G. Ibrahim, M.R. Belkhedkar, Structural, optical and electric properties of nanocrystalline MgSe thin films deposited by chemical route using triethanolamine as a complexing agent, Solid State Science. 23 (2013) 96-108.
[16] A.U. Ubale, V.P. Deshpande, Thickness dependent structural, electrical and optical properties of nanostructured zinc oxide thin films deposited by chemical spray technique, Optoelectronic Advan. Mater. Rapid Commun. 5(2) (2011) 119-124.
[17] A.U. Ubale, Y.S. Sakhare, S.M. Bombatkar, Influence of the complexing agent (Na2-EDTA) on the structural, morphological, electrical and optical properties of chemically deposited FeSe thin films, Mater. Res. Bull. 48 (2013) 3564.
[18] A. Fleszar, LDA, GW, and exact-exchange Kohn-Sham scheme calculations of the electronic structure of sp semiconductors, Phys. Rev. B. 64 (2001) 245204.
[19] H. Okuyama, K. Nakano, T. Miyajima, K. Akimoto, Epitaxial growth of ZnMgSSe on GaAs substrate by molecular beam epitaxy, J. Cryst. Growth 117 (1992) 139.
[20] A.U. Ubale, Effect of complexing agent on growth process and properties of nanostructured Bi2S3 thin films deposited by chemical bath deposition method, Mater. Chem. Phys. 121 (2010) 555-560.
[21] A.U. Ubale, Y.S. Sakhare, M.V. Bhute, et
al., Size-dependent structural, electrical and optical properties of nanostructured iron selenide thin films deposited by Chemical Bath Deposition Method, Solid State Sci. 16 (2013) 134.
THE AUTHORS
SAKHARE Yogesh S.
Department of Engineering Physics, P.R.. Pote College of Engineering & Management. Pote Estate, Kathora Road, Amravati, Maharashtra 444602, India sakhare.yogesh@gmail.com
THAKARE Nilesh R.
Department of Engineering Physics, P.R.. Pote College of Engineering & Management. Pote Estate, Kathora Road, Amravati, Maharashtra 444602, India nileshthakare@gmail.com
UBALE Ashok U.
Nanostructured Thin Film Materials Laboratory, Department of Physics, Government Vidarbha Institute of Science and Humanities.
VMV Road, Amravati, Maharashtra 444604, India ashokuu@yahoo.com
Сахаре Ё.С., Такаре Н.Р., Убале А.У. ВЛИЯНИЕ КОЛИЧЕСТВА РАСПЫЛЯЕМОГО РАСТВОРА НА ФИЗИЧЕСКИЕ СВОЙСТВА ТОНКИХ НАНОКРИСТАЛЛИЧЕСКИХ ПЛЕНОК СЕЛЕНИДА МАГНИЯ, ОСАЖДЕННЫХ МЕТОДОМ СПРЕЙ-ПИРОЛИЗА.
Тонкие нанокристаллические пленки селенида магния MgSe были приготовлены методом спрей-пиролиза с использованием различного количества распыляемого раствора. Рассмотрено влияние изменения количества этого раствора на структурные, электрические, морфологические и оптические свойства пленок MgSe. Методом рентгеновской дифракции установлено, что осажденный MgSe имеет кубическую кристаллическую решетку с преимущественной ориентацией (111). Оптические исследования показали, что для полученного объекта характерна запрещенная зона с прямыми оптическими переходами, ширина которой меняется от 2,45 до 2,75 эВ, в зависимости от количества распыляемого раствора. Электрическое сопротивление пленки MgSe снижается с повышением температуры, что указывает на ее полупроводниковую природу. Установлено, что электросопротивление, энергия активации и ширина запрещенной зоны зависят от количества распыляемого раствора. Измерение термоэдс путем создания температурного градиента через пленку подтвердило, что она проявляет проводимость дырочного типа.
ТОНКИЕ ПЛЕНКИ, ДИФРАКЦИЯ ОПТИЧЕСКИХ ЛУЧЕЙ, ОПТИЧЕСКИЕ СВОЙСТВА.
СПИСОК ЛИТЕРАТУРЫ
[1] Wang M.W., Phillips M.C., Swenberg J.F.,
et al., «-CdSe/p-ZnTe based wide band-gap light emitters: Numerical simulation and design // J. Appl. Phys. 1993.Vol. 73. No. 9. P. 4660.
[2] Ruoff A.L., Li T., Ho A.C., et al., Sevenfold coordinated MgSe: experimental internal atom position determination to 146 GPa. Diffraction studies to 202 GPa, and theoretical studies to 500 GPa // Phys. Rev. Lett. 1998. Vol. 81. No. 13. Pp. 2723-2726.
[3] Prete P., Lovergine N., Tapfer L., et al. MOVPE growth of MgSe and ZnMgSe on (100) GaAs // J. Cryst. Growth. 2000. Vol. 214-215. Pp. 119-124.
[4] Sahraoui Ali F., Arab F., Zerroug S., Louail L. First-principles study of structural and elastic properties of MgSe under hydrostatic pressure
// Comput. Mater. Sci. 2008. Vol. 41. No. 4. Pp. 538-541.
[5] Pandey R., Sutjianto A. Study of structural phase transition in MgSe // Solid State Commun. 1994. Vol. 91. No. 4. Pp. 269-271.
[6] Ubale A.U., Sakhare Y.S. Growth of nanocrystalline MgSe thin films by spray pyrolysis // Vacuum. 2014. Vol. 99. Pp. 124-126.
[7] Takemura Y., Suto H., Honda N., et al., Characterization of FeSe thin films prepared on GaAs substrate by selenization technique // J. Appl. Phys. 1997. Vol. 81. No. 8. P. 5177.
[8] Campos C.E.M., de Lima J.C., Grandi T.A., et al., GaSe formation by mechanical alloying Ga50Se50 mixture // Solid State Commun. 2003. Vol. 126. No. 11. Pp. 611-615.
[9] Ouertani B., Ouerfelli J., Saadoun M.,
Bessais B. Transformation of amorphous iron oxide films pre-deposited by spray pyrolysis into FeS2-pyrite films // Mater. Lett. 2005. Vol. 59. P. 734. 2
[10] Ubale A., Sakhare Y., Belkhedkar M. Synthesis and characterization of spray deposited nanostructured FeSe thin films // Mater. Lett. 2013. Vol. 93. P. 111.
[11] Ouertani B., Ouerfelli J., Saadoun M. Transformation of amorphous iron oxide thin films predeposited by spray pyrolysis into a single FeSe2-phase by selenisation // Sol. Energy Mater. Sol. Cells. 2005. Vol. 87. P. 501.
[12] Wu X., Zhang Z., Zhang J., Ju Z. Structural and electrical characterizations of single tetragonal FeSe on Si substrate // J. Cryst. Growth. 2007. Vol. 300. P. 483.
[13] Ubale A.U., Sakhare Y.S. Thickness dependent physical properties of chemically deposited nanocrystalline MgSe thin films deposited at room temperature by solution growth method // Mater. Sci. Semicond. Processing. 2013. Vol. 16. No. 6. Pp. 1769-1774.
[14] Ubale A.U., Sakhare Y.S. Physical properties of MgSe thin films grown by chemical bath deposition method: effect of molar concentration of MgCl2 // Indian J. Phys. 2013. Vol. 87. No. 12. Pp. 1183-1188.
[15] Ubale A.U., Sakhare Y.S., Ibrahim S.G., Belkhedkar M.R. Structural, optical and electric properties of nanocrystalline MgSe thin films deposited by chemical route using triethanolamine
as a complexing agent // Solid State Science. 2013. Vol. 23. Pp. 96-101.
[16] Ubale A., Deshpande V. Thickness dependent structural, electrical and optical properties of nanostructured zinc oxide thin films deposited by chemical spray technique // Optoelectronic Advan. Mater. Rapid Commun. Vol. 5. No. 2. Pp. 119-124. 2011.
[17] Ubale A., Sakhare Y., Bombatkar S. Influence of the complexing agent (Na2-EDTA) on the structural, morphological, electrical and optical properties of chemically deposited FeSe thin films // Mater. Res. Bull. 2013. Vol. 48. P. 3564.
[18] Fleszar A. LDA, GW, and exact-exchange Kohn-Sham scheme calculations of the electronic structure of sp semiconductors // Phys. Rev. B. 2001. Vol. 64. P. 254204.
[19] Okuyama H., Nakano K., Miyajima T., Akimoto K. Epitaxial growth of ZnMgSSe on GaAs substrate by molecular beam epitaxy // J. Cryst. Growth. 1992. Vol. 117. P. 139.
[20] Ubale A. Effect of complexing agent on growth process and properties of nanostructured Bi2S3 thin films deposited by chemical bath deposition method // Mater. Chem. Phys. 2010. Vol. 121. Pp. 555-560.
[21] Ubale A.U., Sakhare Y.S., Bhute M.V., et al., Size-dependent structural, electrical and optical properties of nanostructured iron selenide thin films deposited by Chemical Bath Deposition Method // Solid State Sci. 2013. Vol. 16. Pp. 134-142.
СВЕДЕНИЯ ОБ АВТОРАХ
САХАРЕ Егеш С. — PhD, доцент факультета инженерной физики Колледжа инженерных наук Р.П. Поте.
Pote Estate, Kathora Road, Amravati, Maharashtra 444602, India sakhare.yogesh@gmail.com
ТАКАРЕ Нилеш Р. — PhD, сотрудник факультета инженерной физики Колледжа инженерных наук Р.П. Поте.
Pote Estate, Kathora Road, Amravati, Maharashtra 444602, India nileshthakare@gmail.com
УБАЛЕ Ашок У. — PhD, сотрудник лаборатории наноструктурных тонкопленочных материалов факультета физики Института естественных и гуманитарных наук правительства Видарбхи. VMV Road, Amravati, Maharashtra 444604, India ashokuu@yahoo.com
© Санкт-Петербургский политехнический университет Петра Великого, 2016
