40220140501005

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40220140501005

  1. 1. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), INTERNATIONAL JOURNAL OF ELECTRICAL ENGINEERING & ISSN 0976 – 6553(Online) Volume 5, Issue 1, January (2014), © IAEME TECHNOLOGY (IJEET) ISSN 0976 – 6545(Print) ISSN 0976 – 6553(Online) Volume 5, Issue 1, January (2014), pp. 35-43 © IAEME: www.iaeme.com/ijeet.asp Journal Impact Factor (2013): 5.5028 (Calculated by GISI) www.jifactor.com IJEET ©IAEME IMPACT OF Sn CONCENTRATION AND HEAT TREATMENT ON STRUCTURAL AND MORPHOLOGICAL PROPERTIES OF THIN Cd1-xSnxSe FILMS M.F.A. Alias, Iqbal S. Naji, Hajir Abd Alsatar Alshamary Physics Department, Science College, University of Baghdad P.O.Box 47162, Jadiriyah,Baghdad / IRAQ ABSTRACT Cadmium tin selenide (Cd1-xSnxSe) alloy are prepared and thin Cd1-xSnxSe films are deposited on a glass substrate at different Sn concentration (x=0.00, 0.25, 0.50, 0.75 and 1.00) by using thermal evaporation technique. The prepared films annealed at temperature equal to 573K and studied the effect of heat treatment on the structural and morphological properties of the prepared films. X-ray diffraction pattern reveals a mix of cubic and hexagonal phases.Morphological test shows the grain size which is almost spherical distributed over the entire surface of the substrate. Keywords: Cd1-xSnxSe Alloys and Films, Heat Treatment, Structural and Morphological Properties. I. INTRODUCTION Cadmium selenide (CdSe) is a direct band gap material semiconductor with band gap energy of 1.74 eV is a II–VI semiconductor compound material with potential applications in low cost electronics and optoelectronics devices such as solar cells , photoconductors , thin film transistors , light emitting diodes biomedical imaging devices , and laser diodes [1-4].Thin films were prepared by various techniques [5-11]. Crystallize CdSe has either the wurtzite (hexagonal structure) which exhibits high resistance against photo-corrosion, or the zinc blende (cubic structure). The cubic structure is metastable and can be transformed to the hexagonal wurtzite structure following an annealing process [12] or mechanically grinding CdSe samples[13]. SnSe is IV-VI a p-type semiconductor has a phase transition from the orthorhombic to the cubic at 813 K [4].SnSe has excellent optical and optoelectronic properties, which is widely used as 35
  2. 2. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 5, Issue 1, January (2014), © IAEME sensor and laser materials, thin films polarizer, thermoelectric cooling materials , photovoltaic cells , memory switching ,solar photovoltaic devices and infrared electronic devices[1,13]. Thin SnSe films were deposited by different methods [14-16] .Thin films of Cd chalcogenides and their combination with elements of groups III–VI have been identified as promising candidates particularly for photoelectrochemical (PEC) applications [17]. Cadmium tin selenide CdSnSe is a promising material for thin film solar cells because of its ability to absorb the visible light due to its graded energy gap [18]. Electrolytic deposition [13] and vacuum evaporation [19] techniques have been employed for deposition of CdSnSe thin films. In the present work, the Cd1-xSnxSe alloys prepared, then films are deposited on glass substrate at different Sn concentration and annealed at 573K .The effect of Sn concentration and annealing temperature on the structural and morphological properties of the prepared film are investigated. II.EXPERIMENTAL PROCEDURE Cd1-xSnxSe compound was synthesized in a quartz tube by taking cadmium metal, tin powder, and selenium powder in their respective stoichiometric ratios as(x=0.00, 0.25, 0.50, 0.75 and 1.00).The tube was evacuated then sealed. It was slowly heated in an electrical furnace at certain temperture and kept it at this temperature for 3 hours. Vacuum thermal evaporation technique was used to deposit Cd1-xSnxSe thin films at room temperature using an Edward coating unit onto cleaned glass substrates at 10-5 mbar. The prepared thin films were annealed under vacuum at temperature (Ta) equal to 573K. X-ray diffraction (XRD)(6000 shimadza) using Cu radiation was used to measure XRD patterns for prepared films. The inter planer distance (d) was calculated using Bragg,s law which is: 2d sin θ = mλ (1) where m is integer, θ is the Bragg angle and λ is wavelength. D is the grain size, in a polycrystalline film is measured by Scherer's formula: (2) where ∆ (2θ) is the full width at half maximum (in radians) of the peak. Morphological test was examined by atomic force microscopy (AFM) using scanning probe microscope type (AA3000) to study the effect of annealing temperature on the morphological properties. III. RESULTS AND DISCUSSION X-ray diffraction experiments have been carried out in order to study the structural properties of the prepared Cd1-xSnxSe alloys and films, i.e, to investigate the crystallographic phase, the overall crystalline quality, and the possible texture of those thin films. Fig.(1) shows the X-ray diffraction for thin Cd 1-xSnxSe alloys.The sharp peaks present in XRD patterns indicate that the films are polycrystalline in nature and the preferred orientation is along (111) for x=0.25, 0.5 and 0.75.This result is agreed with that observed by Shaban[18].At 36
  3. 3. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 5, Issue 1, January (2014), © IAEME x=0.0, the preferred orientation is along (100) while for x=1 is (040).All the concentration confirm a mix phase of hexagonal and orthorhombic structure. Fig.(2) show the XRD pattern for thin Cd1-xSnxSe films at x=0.0 shows the preferred orientation is along (002) and other weak peaks (100),(101) and (013)planes and the intensity increased with the annealing and become more clear and sharp.All the peak were hexagonal phase. Fig.(3) shows XRD pattern for thin Cd1-xSnxSe film for x=0.25, at room temperature and annealed at 573K. It shows hexagonal and orthorhombic phases of the film with preferred orientation along (002).Another weak peaks are observed at plans orientation which are (100),(111),(040),(110) and (112) planes. For the results obtained for thin film for x=0.00 and x=0.25 agreed with that shown by Kissenger et al [5], Patil et al[9] and Vishwakarama et al [20].They found the preferred orientation along (002) planes. Fig.(4) show the XRD pattern for thin Cd1-xSnxSe film for x=0.50 deposited at room temperature and annealed at 573K.It showed amorphous nature at room temperture and after the annealing .The films has preferred orientation along (002) and (111) Another peaks are observed at (100),(101),(040),(041),(110),(200) and(112).It shows mix phase of hexagonal and orthorhombic. This results agreed with Vishwakarama et al [20], which found the preferred orientation along (002) planes for CdSe, while Butt et al [14] have found preferred orientation along (111) for SnSe. The Preferred orientation along (111) and (040) planes for thin Cd1-xSnxSe film for x=0.75 as showed in Fig.(5). It shows orthorhombic phase for the thin film, before and after the annealing. These results are agreed with Shaban et al [18] and Dhanasekaran et al [2]. Fig.(6) shows a XRD pattern for thin SnSe film, at room temperature and annealed at temperture equal to 573K. It shows amorphous nature at room temperture and after the annealing temperture the film showed prefertial orientation along (111) plane which confirm the orthorhombic phase. These results are agreed with Mariappan et al [16] and Butt et al [14]. Tables (1) illustrate the parameters of XRD investigation as affected by Sn concentration and annealing temperature on thin Cd1-xSnxSe film. It is clear from this Table that all the concentration, the grain size and the intensity of the peak increase with increasing the anealing temperture. The topography of the film surfaces has been displayed in the AFM images. The images confirm the formation of spherically shape. The grains size are small with uniform morphology and well-defined grain boundaries are observed before the annealing and become too clear after the annealing except for x=1 (SnSe) show amorphous surface with out well -defined grain boundaries before the annealing and that change after the annealing process. This agreed with result obtained from X-ray diffraction investigation. All the films reveal that the films have uniform distribution of grain size over total coverge of the substrate with compact and fine grained morphology and homogeneous, with out cracks or holes and well covered to the glass substrate. Fig.(6 )shows the AFM images for preaperd thin Cd1-xSnxSe films with all concentration of Sn (x=0, 0.25,0.50, 0.75 and .01) which show the effect of annealing on the average crystallite. Table (2) show the effect of x and annealing temperature on the average crystalline and average roughness. It shows from the images and Table that for x=0.0, x=0.50, x=0.75 and x=1.0 the average crystalline and roughness decrease after annealed, while increase for x=0.25. 37
  4. 4. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), al ISSN 0976 – 6553(Online) Volume 5, Issue 1, January (2014), © IAEME Fig.(1) X-ray diffraction for Cd1-xSnxSe alloy at different Sn concentration ray Fig.(2) X-ray diffraction for CdSe thin films as deposited and annealed at 573K ray Fig.(3) X-ray diffraction for thin Cd1-xSnxSe film for x=0.2 ray 25. 38
  5. 5. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), al ISSN 0976 – 6553(Online) Volume 5, Issue 1, January (2014), © IAEME Fig.(4) X-ray diffraction for thin Cd1-xSnxSe film at x=0.50 ray Fig.(5) X-ray diffraction for thin Cd1-xSnxSe film at x=0.75. ray Fig.(6) X-ray diffraction for thin Cd1-xSnxSe film at x=1. ray 39
  6. 6. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 5, Issue 1, January (2014), © IAEME Table.1: The effect of Sn concentration and heat treatment on XRD parameters for thin Cd1-xSnxSe film x T (K) FWHM dhkl Exp (Å) D (Å) dhkl Std (Å) hkl phase 23.901 0.462 3.708 165 3.7226 (100) Hex-CdSe 25.272 25.354 0.324 3.521 237 3.5076 (002) Hex-CdSe 27.029 0.00 2θth (Deg.) 23.977 R.T 2θexp (Deg.) 27.080 0.462 3.296 166 3.2883 (101) Hex-CdSe 0.740 1.979 110 1.9801 (013) Hex-CdSe (100) Hex-CdSe 45.803 23.918 573 25.417 27.110 23.901 27.080 46.022 24.095 25.666 R.T 30.379 31.108 23.901 25.354 3.717 226 0.193 3.501 397 3.5076 (002) Hex-CdSe 0.435 3.287 177 3.2883 (101) Hex-CdSe 0.580 25.354 0.339 3.7226 1.971 140 1.9801 (013) Hex-CdSe 0.449 3.690 171 3.7226 (100) Hex-CdSe (002) Hex-CdSe 30.644 42.328 44.073 3.468 137 0.505 2.940 154 2.9527 (111) Orth-SnSe 0.393 2.873 198 2.8925 (040) Orth-SnSe 0.505 30.283 0.561 3.5076 2.134 159 2.1493 (110) Hex-CdSe 0.729 2.031 111 2.0540 (150) Orth-SnSe 23.792 23.901 0.409 3.737 187 3.7226 (100) Hex-CdSe 25.272 25.354 0.462 3.521 166 3.5076 (002) Hex-CdSe 30.358 30.283 0.324 2.942 240 2.9527 (111) Orth-SnSe 30.775 30.644 0.356 2.903 218 2.8925 (040) Orth-SnSe 0.416 2.381 190 2.3804 (041) Orth-SnSe 0.509 2.149 158 2.1493 (110) Hex-CdSe 0.601 1.837 137 1.8326 (112) Hex-CdSe 44.572 0.25 573 37.757 42.012 49.595 R.T 49.699 - - - - - 23.901 0.462 3.687 165 3.7226 (100) Hex-CdSe 25.364 25.354 0.555 3.509 138 3.5076 (002) Hex-CdSe 29.526 27.080 0.370 3.023 209 3.0538 (101) Orth-SnSe 30.451 573 - 24.116 0.50 - 30.283 0.462 2.933 168 2.9527 (111) Orth-SnSe 30.913 30.644 0.324 2.890 240 2.8925 (040) Orth-SnSe 37.803 R.T 573 (041) Orth-SnSe 0.647 2.151 124 2.1493 (110) Hex-CdSe 48.845 0.462 1.905 177 1.8613 (200) Hex-CdSe 49.699 0.925 1.830 89 1.8326 (112) Hex-CdSe 29.930 30.283 0.912 2.983 85 2.9527 (111) Orth-SnSe 30.497 30.283 0.277 2.929 280 2.9527 (111) Orth-SnSe 31.006 1.00 2.3804 49.780 573 156 47.699 R.T 2.378 41.965 0.75 0.509 41.968 30.644 0.555 2.882 140 2.8925 (040) Orth-SnSe - - - - - - 92 2.9527 (111) Orth-SnSe 30.491 30.283 0.842 2.929 40
  7. 7. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 5, Issue 1, January (2014), © IAEME (a) Ta=375K R.T (b) R.T R.T Ta=573K (c) R.T R.T Ta=573K 41
  8. 8. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 5, Issue 1, January (2014), © IAEME (d) R.T R.T R.T Ta=573 K (e) Ta=573K R.T Fig.(7) AFM images for thin Cd1-xSnxSe films at R.T, 573K and different Sn concentration (a) x=0.0 (b) x=0.25 (c) x=0.50 (d) x=0.75 (e) x=1.0 Table.2: The effect of heat treatment on average crystalline and roughness for thin Cd1-xSnxSe films Ta (K) x Average crystallite(nm) Average roughness R.T 573 0.00 0.25 0.50 0.75 1.00 0.00 0.25 0.50 0.75 1.00 100.83 86.86 72.51 80.12 109.89 92.46 103.28 72.60 80.94 75.17 42 1.73 0.477 0.501 0.453 0.904 0.186 1.51 0.244 0.421 0.735
  9. 9. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 5, Issue 1, January (2014), © IAEME IV. CONCLUSIONS Thin Cd1-xSnxSe films are prepared from prepared alloys at various Sn concentration and heat treatment. In general the structure for all prepared films at different Sn concentration has a mix phase of hexagonal and orthorhombic structure. The grains size are small within nano scale and uniform morphology and well-defined grain boundaries are observed before the annealing and become too clear after the annealing except for x=1. REFERENCES [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] R. Mariappan, V.Ponnuswamy and N. M.Ragavendar, Materials Science in Semiconductor Processing, 15, 2012, 199–205. V. Dhanasekaran, T. Mahalingam , R. Chandramohan, J. P. Chu and Jin-Koo Rhee, Mater Electron, 23, 2012,645–651 F. Zhaoa, B. Tanga, J. Zhangb and Y.Linb , Electrochimica Acta, 62, 2012, 396– 401. N. Boscher, C. Carmalt, R. Palgrave and I. , Thin Solid Films 516 ,2008, 4750–4757. N. Kissinger, M. Jayachandran, K. Perumal and C Sanjeeviraja Bull. Mater. Sci., 30(6), 2007, 547–551. A. Yadav ,M. Barote ,E. Masumdar, Materials Chemistry and Physics, 121, 2010,53-57. D. Dwivedi , V. Kumar, M. Dubey, H. Pathak, Chalcogenide Letters, 8( 9), 2011, 521 – 527. M. A. Rasheed, Kurdistan Academicians Journal, 3(1) Part A, 2004, 41-49. V. T. Patil, Y. R. Toda, V. P. Joshi, D. A. Tayade, J. V. Dhanvij, D. N. Gujarathi, Chalcogenide Letters, 10(7) 2013, 239 – 247. G. Perna, V. Capozzi, M. Ambrico, V. Augelli, T. Ligonzo,A. Minafra, L. Schiavulli, M. Pallara, Applied Surface Science, 233,2004, 366–372. R. Henriquez, A. Badan, P. Grez, E. Mu˜noz, J. Vera, E.A. Dalchiele, R.E. Marotti, H. Gomez, Electrochimica Acta, 56 , 2011, 4895–4901. M.D. Athanassopoulou, J.A. Mergos, M.D. Palaiologopoulou, Th.G. Argyropoulos, C.T. Dervos , Thin Solid Films,520 ,2012, 6515–6520. Kriti Sharma, Alaa S. Al-Kabbi, G.S.S. Saini, S.K. Tripathi, Materials Research Bulletin, 47, 2012, 1400–1406. Faheem K. Butt , Chuanbao Cao , Waheed S. Khan , Zulfiqar Ali , R. Ahmed, Faryal Idrees, Imran Aslam , M. Tanveer , Jili Li , Sher Zaman ,Tariq Mahmood, Materials Chemistry and Physics , 137 ,2012,565-570. N.A. Okereke, A. J. Ekpunobi, Chalcogenide Letters, 7( 9) ,2010,531 -538. R. Mariappan, M. Ragavendar, G. Gowrisankar, Chalcogenide Letters, 7(3), 2010, 211 – 216. J. Datta, C. Bhattacharya, S. Bandyopadhyay, Applied Surface Science 252, 2006, 7493– 7502. S. Shaban, R. M.SALEH and A. Ahmed, Turks Phys. 35, 2011, 189 – 196. X. He , H. Shen , W. Wangb, Z. Wang , B. Zhang , X. Li , Journal of Alloys and Compounds 556 ,2013, 86–93. S. Vishwakarma, A. Kumar, S.Das, A. Verma, R.Tripathi, Chalcogenide Letters, 10(7) 2013, 239 – 246. Sundus M. A. Al-Dujayli, Nathera A. Al- Tememee, Ghuson H. Mohamed, Bahaa T. Chiad, Firas J. Kadhim and Bashair Abdul Rahman, “Morphological and Electrical Properties of SP Deposited Cadmium Sulphide Thin Films”, International Journal of Advanced Research in Engineering & Technology (IJARET), Volume 4, Issue 4, 2013, pp. 38 - 49, ISSN Print: 0976-6480, ISSN Online: 0976-6499. 43

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