Mar 18, 2016 - Growth, Optical and Electirical Properties of In2Se3 Thin Films by the (SILAR) Method ... Thin Films Developed by Using Spraying Method.
Investigation of Structural and Optical Properties of InP Thin Films Developed by Using Spraying Method Funda Aksoy, Refik Kayali, Mustafa Öztaş, and Metin Bedir Citation: AIP Conference Proceedings 899, 231 (2007); doi: 10.1063/1.2733121 View online: http://dx.doi.org/10.1063/1.2733121 View Table of Contents: http://scitation.aip.org/content/aip/proceeding/aipcp/899?ver=pdfcov Published by the AIP Publishing Articles you may be interested in Physical properties of Cu2ZnSnS4 thin films deposited by spray pyrolysis technique J. Renewable Sustainable Energy 5, 023113 (2013); 10.1063/1.4795399 Structural, optical, and electrical properties of Yb-doped ZnO thin films prepared by spray pyrolysis method J. Appl. Phys. 109, 033708 (2011); 10.1063/1.3544307 Influence of the oxidation conditions on the structural characteristics and optical properties of zinc oxide thin films J. Vac. Sci. Technol. A 28, 1344 (2010); 10.1116/1.3484243 Growth, Optical and Electirical Properties of In2Se3 Thin Films by the (SILAR) Method AIP Conf. Proc. 899, 579 (2007); 10.1063/1.2733320 Physical Properties of Thin Film Semiconducting Materials AIP Conf. Proc. 795, 196 (2005); 10.1063/1.2128326
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Investigation of Structural and Optical Properties of InP Thin Films Developed by Using Spraying Method Funda Aksoy*, Refik Kayah*, Mustafa Oztas** and Metin Bedir** *Nigde University. Faculty of. Art and Sciences.Department of Physics, NlGDE **Gaziantep University. Department of Physics Engineering, GAZIANTEP Abstract. Structural and optical properties of InP films developed with the solutions prepared with InCl3 and C12HP04 salts having different rates by using spraying method have been investigated using the data obtained from UV spectrometer and XRD (x-ray difractometer). Band gap energy values of all samples obtained by using UV spectrometer are found in 1.60-1.85 eV range. It was observed that basic piks of all samples are in (200) plane and have a fee structure in the XRD analysis. In addition, grain size of the samples increases with the rate of indium included in samples and it is seen that the crystallization in surface structure tends to become more homogenity. Keywords: InP, spraying method, UV spectrometer, XRD PACS: 70
INTRODUCTION
100
Semiconductor crystals have been intensively investigated recently due to their novel properties that are markedly different from those of the bulk solids [1-2]. Among them, III-V group semiconductor nanocrystals, with more distinct quantum confinement effect, are likely to be the most promising candidates for fabricating nanoscale optoelectronic devices. Up to now, many researchers who have studied on InP fabrication using different methods have been reported [3,4]. In this work, we report the structural and optical properties of InP thin films prepared by spray pyrolysis method.
Wavelength (nm)
FIGURE 1. Optical transmittance T (%) spectra of InP thin films deposited at different ratios of indium and phosphat.
EXPERIMENTAL
A weak change in the absorption edge is observed towards higher wavelengths as the ratios of indium increases. The transmission decreases from 80% at In:P;3:l to 68% at In:P;10:l. It is seen that as the ratio of indium of the film increases the interference effects also become prominent. The transmission of InP thin films is strongly influenced by the ratios of indium and phosphat. It is observed that the transmittance of films increase as the ratios of indium increases. It can also easily be seen from Table 1[4]. This improvement can be attributed to the perfection and stoichiometry of the films. The absorption coefficient was calculated and plotted for allowed direct transitions (neglecting exciton effects) by using the expression as a function of photon energy [5].
The thin films of InP were deposited with spraying solutions prepared with different rates of In and P onto a 1 cm2 heated glass substrate at 500°C substrate temperature. The structural properties of the films were studied by X-ray analysis with a Rigaku D/MaxIIIS model X-ray diffractometer $,=1.5405 A0). The optical absorption spectra of the films were obtained using Perkin Elmar Lambda 25 UV-VIS-NIR doublebeam spectrophotometer having a wavelength range of 240-2400 nm.
RESULTS AND DISCUSSION Optical characterization Optical absorption studies of InP thin films deposited on the glass substrates were carried out in the wavelength (X) range 750-1350 nm at room temperature. The optical transmission spectra of the films prepared at different rates are shown in Fig.l.
(ahvf =A(hv-Eg)
(1)
CP899, Sixth International Conference of the Balkan Physical Union, edited by S. A. Cetin and I. Hikmet © 2007 American Institute of Physics 978-0-7354-0404-5/07/$23.00 231 Reuse of AIP Publishing content is subject to the terms at: https://publishing.aip.org/authors/rights-and-permissions IP: 194.27.42.224 On: Fri, 18 Mar 2016 13:50:16
TABLE. 1 Structural and optical properties of InP thin films at various substrate temperatures. In:P
Grain Size(A)
Band gap (eV)
Trans.(%)
10:5
11,92
1,69
72
10:1
12,87
1,61
68
5:1
11,27
1,72
70
3:1
9.68
1,8
80
with cubic crystal structure. It is obvious that the growth of the InP thin film samples is very dependent on the ratios of indium and phosphat.
I^PCIO^D
In:PC10:nC
Figure 2 shows that the dependences of (ahv) as a function of photon energy hv indicates the direct nature of band-to-band transitions for the studied samples.
(2001
-M
In:Pr5:nB
Hut |iilHYH'ili»f-|irf^irlil»-|' i
(2001
In:Pf3:n 29 meprees'l
FIGURE 3. X-ray diffraction patterns of InP thin films grown at different ratios of indium and phosphat: (a) 3:1, (b) 5:1, (c) 10:1 and (d) 10:5 Energy (eV)
CONCLUSION
FIGURE 2. (ahv) 2 versus hv for InP thin films deposited at different ratios of indium and phosphat: (a) 3:1, (b) 5:1, (c) 10:5 and (d) 10:1 The values of optical band gap, Eg have been determined by extrapolating the lineer portions of respective curves to (ahv) 2 -^ 0. It is seen from the Table 1 that the band gap energy is decreased from 1,80 eV to 1,60 eV as the ratios of In and P are increased from the 3:1 to 10:1 respectively. These results are in a god agreement with the other results[5].
InP thin films have been prepared by the spray pyrolysis method on glass substrates with different rates at 500°C substrate temperature. The X-ray diffraction measurements of the obtained thin films showed that the crystalline state of InP is improved with the increasing the ratio of indium. However, optical measurements featured that the optical band gap decreases from 1.80 to 1.60 eV when the ratio of indium increases. From this study, it can be concluded that the ratio of indium and phosphat has a strong influence on the structure and consequently the optical properties of InP thin films [7]. The influence of the different rates of In:P on the structural and optical properties of InP thin films like a window material will be useful for the formation of InP-based heterostructure for the application of optoelectronic devices.
X R D characterization The as-grown InP thin films deposited at various ratios were characterized by the XRD technique scanned in the 26 range of 20°-50°. The diffractograms were obtained for the films grown on the amorphous glass plates (Fig. 3). The diffractograms depict that the deposits are polycrystalline for all the ratios. The spectra clearly show that the films formed at different ratio at the 500°C substrate temperature exhibit a strong peak around 30.36° corresponding to the (200) plane of polycrystalline indium phosphide, whereas the intensity of its reflection increases with the ratio of indium. Thin films fabricated at these conditions are rather homogenous, and their crystalline state improves when the ratio of indium increases [6]. This increase can be correlated with the increase of the grain size as shown in Table 1. A well matching of the observed and the standard '(i-values' confirms the formation of compound InP
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