Conseguences of soil crude oil pollution on some wood properties of olive trees Physics | 53 2012( عام 1العدد ) 30صرفة و التطبيقية المجلدمجلة إبن الهيثم للعلوم ال Ibn Al-Haitham J. for Pure & Appl. Sci. Vol.30 (1) 2017 The Effect of the (Se) percentage on Compositional, Morphological and structural properties of Bi2(Te1-xSex)3 thin films Ikhlas H.Shallal Dept. of Physics/ College of Education for Pure Science /(Ibn Al-Haitham)/ University of Baghdad Falah I.Mustafa Al-Attar Solar Energy Research Center, Renewable Energy Directorate, Ministry of Higher education and Scientific Research, Baghdad, Iraq Hadeel F. Hussain Dept. of Physics/ College of Education for Pure Science /(Ibn Al-Haitham)/ University of Baghdad, Iraq Received in :3/October/2016,Accepted in:18/December/2016 Abstract Alloys of Bi2[Te1-x Sex]3 were prepared by melting technique with different values of Se percentage (x=0,0.1,0.3,0.5,0.7,0.9 and 1). Thin films of these alloys were prepared by using thermal evaporation technique under vacuum of 10 -5 Torr on glass substrates, deposited at room temperature with a deposition rate (12nm/min) and a constant thickness (450±30 nm). The concentrations of the initial elements Bi, Te and Se in the Bi2 [Te1-x Sex]3 alloys with different values of Se percentage (x), were determined by XRF,The morphological and structural properties were determined by AFM and XRD techniques. AFM images of Bi2[Te1-x Sex]3 thin films show that the average diameter and the average surface roughness increase with the increase of the percentage of Se. The X–ray diffraction measurements for bulk and thin films of Bi2[Te1-xSex]3 have polycrystalline structure with rohmbohedral structure, with space group R 3 m, and a strong (015) preferred orientation, the crystallite increase with the increase of Se percentage . Keywords :Bismuth Selenide, Cadmium Selenide, thermoelectric, thin films, thermal evaporation, structural properties. Physics | 54 2012( عام 1العدد ) 30صرفة و التطبيقية المجلدمجلة إبن الهيثم للعلوم ال Ibn Al-Haitham J. for Pure & Appl. Sci. Vol.30 (1) 2017 Introduction Scientists and researchers recently focused on the study and expand both clean and renewable energies, and tended to diminish the credence on energy that is produced from fossil fuels (e.g. oil ,gas, petroleum and coal etc). Also because of the negatively effect on the surrounding environment for this type of fuel and in turn on human ,therefore the most frequent type of energy that scientists and researchers had concerned since 1950, was the energy that produced by thermoelectric devices, in which the materials have a thermoelectric properties, this means, materials which are able to make thermal energy to be direct conversion into electrical energy and vice versa[1]. In 1954Goldsmid demonstrated the excellent thermoelectric properties of Bismuth Telluride, attributed mainly to the large mean molecular mass, low melting temperature and partial degeneracy of the conduction and valence bands of this V-VI chalcogenide .Since that, bismuth telluride has been widely studied as a thermoelectric material with a narrow band gap, particularly in the temperature range around 300 K[2,3]. Bi2Te3 or Bi2Se3 has a rombohedral structure with space group R 3 m, and the lattice is stacked in a repeated sequence of five atom layers: Te 1 -Bi-Te 2 - Bi-Te 1 along the c-axis, Te or and (Se) and Bi layers are held together by strong ionic-covalent bonds (Te 1 or\ and Se 1 -Bi and Bi_Te 2 or \and Se 2 ), while The Te 1 or\and Se 1 bonds between cells are of the Van der Walls type and are extremely weak [4, 5]. Bismuth telluride compounds can be doped as either n- or p-type material by creating either a tellurium-rich composition or a bismuth- rich composition respectively [6]. The aim of study The aim of this study is to produce thermoelectric Bi2(Te1-xSex)3 thin films using thermal evaporation technique ,and look into the effectiveness of (Se) percentage on the structural properties , in order to use it in the future to make thermoelectric devices, which were very effective to provide a clean renewable energies to ensure a clean surrounding environment . Experimental Procedure Alloys of Bi2[Te1-x Sex]3 were fabricated by using exact amount of high purity (99.99%) powders of source materials (Bi, Te and Se elements ), accordance with their atomic percentages of Se (x=0,0.1,0.3,0.5,0.7,0.9 and 1), Each alloy was put in an evacuated quartz ampoule to vacuum ~10 -4 Torr , then put them in thermal oven to temperature of 923 K (650 °C) for 6 hours until ensuring homogeneous components and fused with each other, then leave them cooled gradually until they reached room temperature. The alloys were grinded well until they became powder to be manufacture a Bi2[Te1-x Sex]3 thin films with thicknesses (450±30 nm) which were deposited at room temperature on corning 7059 microscopic glass substrate by thermal evaporation method under suitable vacuum (10 -5 Torr). The compositional, morphological and structural properties had been tested by XRF, AFM and XRD techniques. Results and Discussion The concentrations of the initial elements Bi, Te and Se in the Bi2 [Te1-x Sex]3 alloys with different values of Se percentage (x) where (x=0,0.1,0.3,0.5,0.7,0.9 and 1), were determined by XRF, the results were tabulated in Table (1) ,it can be noticed that the compositional analysis of these alloys are in good stoichiometric percentage compared with the theoretical atomic percentages. The AFM test show increasing of the diameter and the roughness of Bi2[Te1-xSex]3 thin films with the increase of the Se percentage as shown in the figure (1), and this result agree with the results of XRD measurements and also agree with references[7,8]. The results of AFM measurement of Bi2[Te1-xSex]3 thin films are listed in table (2). XRD technique has been used to calculate the miller coefficients by using the relation between the intensity and 2ϴ for all samples of Bi2[Te1-xSex]3 alloys and thin films with different values of Physics | 55 2012( عام 1العدد ) 30صرفة و التطبيقية المجلدمجلة إبن الهيثم للعلوم ال Ibn Al-Haitham J. for Pure & Appl. Sci. Vol.30 (1) 2017 Se percentage (x=0,0.1,0.3,0.5,0.7,0.9 and 1). The XRD patterns of Bi2[Te1-xSex]3 alloys showed a rombohedral structure with space group R 3 m, and with a strong (015) preferred orientation ,the observed peaks have been analyzed and indexed using standard pattern Joint Committee on Powder Diffraction Standards (JCPDS) as shown in figure (2) and we noticed the peak (015) moves towards the larger 2ϴ when Se percentage increases , agree with references [9,10,11],and that means there is an effect on the structure properties because of the increasing of the Se percentage . The values of the crystalline size determined by Scherrer formula that presented by (1) [12], and we found that the grain size increase with the increase of the Se percentage (table 3). G.S= Where :Full width at half maximum intensity ϴ: Bragg angle (degree) λ : wavelength (nm) The XRD of Bi2[Te1-xSex]3 thin films have a polycrystalline structure with rohmbohedral structure, and it can be noticed that the main peak in all films is (015) as shown in table (3) and the observed peaks have been analyzed and indexed using standard pattern(JCPDS) as shown in figure(4).Also the test is shown by using Scherrer formula, the crystallite is increasing as function of Se percentage, agrees with[13], that’s mean the percentage of Se is affected on the structural properties of films as shown in Table (4). Conclusions We can summarize the results of the present work as follows: The compositional analyses of Bi2[Te1-xSex]3 alloys are in good stoichiomertric percentage compared with the theoretical atomic percentage. The AFM measurement shows an increase of the diameter and the roughness of Bi2[Te1-xSex]3 thin films were the increase of (Se) percentage. The structural properties of Bi2[Te1-xSex]3 alloys and thin films which prepared with different x percentages (x=0 , 0.1 ,0.3 ,0.5 ,0.7,0.9 and 1) by thermal evaporation technique, were by XRD technique confirmed that all alloys and thin films have a rhombohedral structure with R 3 m space group with a preferred orientation along (015), and we found that the main orientation for all samples was 015 , so the Se percentage affects the structure of the studied alloys and thin films. References 1- Rowe, D. M.,(1995) in CRC Handbook of Thermoelectrics, Boca Raton, 90. 2- Arivouli, D.;Gnanam F. D.; Ramasamy P.; Mater J., (1988).'' Growth and microhardness studies of chalcogneides of arsenic, antimony and bismuth " Sci.Lett", 7, 711-713. 3- Elahi, S. M.; Taghizadeh A.; Hadizadeh A. and Dejam L. (2014),'' Effect of Thickness and Annealing on Structural and Optical Properties of Bi2Te3 Thin Films Prepared from Bi2Te3 Nanoparticels'' Int. J. "Thin Film. Sci.Tec." 3( 1), 13-18 4- Hasan, M.Z., Kane C.L., (2010) ''Topological Insulators'' 2010, Rev.Mod.Phys.82:3045. 5- Zhang, W.; Yu R., Zhang H-J.; Dai X. ;and Fang Z., (2010), ''Quantized anomalous Hall effect in magnetic topological insulators'', New J. Phys., 329(61), 4. 6- Lovett, D. R., (1977),'' semi metals and Narrow Band – Gap Semiconductors'', Pion Limited, London, 181. 7- Neuberger, M., (1966), ''electronic properties information center, the system of Bismuth Telluride and Bismuth Selenide'' , data sheet Ds-147. Physics | 56 2012( عام 1العدد ) 30صرفة و التطبيقية المجلدمجلة إبن الهيثم للعلوم ال Ibn Al-Haitham J. for Pure & Appl. Sci. Vol.30 (1) 2017 8- Hussain, Kh.Rasheed; Ghuson H .Mohamed ;and Khalil I. Inad, ( 2014), ''Dependence of Structure and Optical Characterization of Bi2Te Films Prepared by Flash Evaporation on Annealing Temperatures'', Eng. &Tech. Journal, 32, Part (B), 4, 729-736. 9- Khalil Ibrahim Inad, (2014), "Study thermoelectrical characterization (Bi2Te3),(Bi2Te3)xSb1-x and (Bi2Te3)xSe1-x as a Peltier device", Baghdad University, PhD thesis. 10- Dheepa, J.; Sathyamoorthy R.; Subbarayan A.; and Natarajan K. (2004), ''Transport Properties of Sb2Te3 Doped Bi2TeThin Films'' ,solar energy materials and solar cells. 81 , 305_312. 11-. Zou H, Rowe D.M; and Min G, (2001),'' Growth of p- and n-type bismuth telluride thin films by co-evaporation'', Journal of Crystal Growth , 222 (1-2) 82-87 12- Shafai C.; and Brett M.J., (1999) , Optimization of Bi2Te3 thin films for microintegrated Peltier heat pumps, ''J. Vac. Sci. Technol'', 15, 2798 13- Zhang G.; Qin H.; Teng J.; Jiandong G.; Qinlin; G. Xi.; Fang Z.;, and Wua K., (2009) , ''Quantized anomalous Hall effect in magnetic topological insulators ",App. PHYS LETT. 95(5),3114, . Table (1) The theoretical and experimental atomic percentage of Bi2 (Te1-x Se x)3 alloys Alloys Elements Atomic percentage % Theoretical Experimental Bi2Te3 Bi 40 42.6 Te 60 57.4 Bi2(Te0.9 Se 0.1)3 Bi 40 41.9 Te 50 47.2 Se 10 11.8 Bi2(Te0.7 Se 0.3)3 Bi 40 41.4 Te 40 37.1 Se 20 21.5 Bi2(Te0.5 Se 0.5)3 Bi 40 41.08 Te 30 31.7 Se 30 27.62 Bi2(Te0.3 Se 0.7)3 Bi 40 41.1 Te 20 19.2 Se 40 39.7 Bi2(Te0.1 Se 0.9)3 Bi 40 40.9 Te 10 10.2 Se 50 48.9 Bi2Se3 Bi 40 40.02 Se 60 59.88 Physics | 57 2012( عام 1العدد ) 30صرفة و التطبيقية المجلدمجلة إبن الهيثم للعلوم ال Ibn Al-Haitham J. for Pure & Appl. Sci. Vol.30 (1) 2017 X hkl 2Ө(exp)(degree) d value (stand.)(A°) d d value (exp) (A°) I/I°(a.u) 0 0015 44.57 2.07 2.031 45% 015 28.22 3.205 3.220 100% 006 17.51 4.777 5.060 45% 0.1 015 28.32 3.12 3.230 100% 0015 44.6 3.12 3.132 85% 006 17.52 2.31 2.326 42% 0.3 015 28.62 2.562 2.829 100% 006 38.56 1.283 1.268 32% 0015 50.40 1.808 1.808 45% 0.5 006 18.23 4.85 4.783 13% 015 28.78 3.074 3.045 85% 0015 45.26 2.133 2.242 60% 0.7 006 17.4 5.1 4.728 40% 0015 47.72 2 1.903 45% 015 28.9 3.22 3.024 100% 0.9 006 18.53 3.74 4.783 62% 015 29.03 3.237 3.044 87% 0015 46.17 2.19 2.242 50% 1 006 18.75 3.205 4.728 60% 0015 47.72 3.599 1.903 58% 015 29.51 3.183 3.024 100% X D (nm) Roughness 0 74 0.375 0.1 75.65 0.4 0.3 79.08 0.434 0.5 80 1.96 0.7 82 2.02 0.9 92.96 2.19 1 102.63 5.48 Table (3) The parameter of 2ϴ ,hkl, the interplaner of the crystals d and the grain size G.S (nm) of Bi2(Te1-xSe x)3 alloys Table (2) The AFM results showing the grain size and the roughness of Bi2(Te 1-x Se x)3 thin films Physics | 58 2012( عام 1العدد ) 30صرفة و التطبيقية المجلدمجلة إبن الهيثم للعلوم ال Ibn Al-Haitham J. for Pure & Appl. Sci. Vol.30 (1) 2017 X hkl 2ϴ dXRD DASTM G.S (nm) I/I° (a.u) 0 015 26.5833 3.350 3.222 9.8 100% 1010 34.3722 3.649 20% 101 21.5087 4.128 10% 0.1 015 27. 2 3.249 3.074 10.7 100% 1010 38.1402 2.357 40% 101 22.12 4.128 42% 0.3 015 28.02 3.182 3.074 12.8 100% 1010 38.56 4.575 45% 101 23.13 3.842 40% 0.5 015 28.1059 3.172 3.074 10.2 80% 101 23.2672 3.267 30% 1010 39.4093 2.284 25% 0.7 101 21.46 3.235 3.047 11 70% 015 28.6751 3.110 100% 1010 40.0139 2.251 60% 0.9 015 29.16 3.06 3.074 11.7 100% 101 22.86 3.21 40% 1010 40.3536 2.23 30% 1 1010 47.311 3.26 3.205 20.4 20% 101 22.5585 3.94 80% 015 29.2462 3.16 100% Table (4) the parameter of 2ϴ, hkl, the interplaner of the crystals d and the grain size G.S (nm) of Bi2(Te1-xSe x)3 thin films Physics | 59 2012( عام 1العدد ) 30صرفة و التطبيقية المجلدمجلة إبن الهيثم للعلوم ال Ibn Al-Haitham J. for Pure & Appl. Sci. Vol.30 (1) 2017 Figure (1) AFM pattern of Bi2(Te1-x Sex)3 thin films with different (Se) percentages. a) x= 0,0.1,0.3,0.5 and b) x= 0.7,0.9,1.0. a b Physics | 60 2012( عام 1العدد ) 30صرفة و التطبيقية المجلدمجلة إبن الهيثم للعلوم ال Ibn Al-Haitham J. for Pure & Appl. Sci. Vol.30 (1) 2017 Figure ( 2) XRD patterns for Bi2(Te1-x Sex)3 alloys with different (Se) percentage. Physics | 61 2012( عام 1العدد ) 30صرفة و التطبيقية المجلدمجلة إبن الهيثم للعلوم ال Ibn Al-Haitham J. for Pure & Appl. Sci. Vol.30 (1) 2017 Figure (3) XRD patterns of Bi2(Te1-x Sex)3 thin films with different (Se) percentages Physics | 62 2012( عام 1العدد ) 30صرفة و التطبيقية المجلدمجلة إبن الهيثم للعلوم ال Ibn Al-Haitham J. for Pure & Appl. Sci. Vol.30 (1) 2017 انرقيقة Bi2(Te1-x Sex)3( عهى انخواص انسطحية وانتركيبية الغشية Seتأثير وسبة ) اخالص هميم شالل جايعت بغذاد )ابٍ انهُثى(/ كهُت انخشبُت نهعهىو انصشفت /قسى انفُضَاء فالح مصطفى انعطار وصاسة انعهىو وانخكُهىجُا/ دائشة بحىد انطاقت انًخجذدة /يشكض بحىد انطاقت انشًسُت هديم فاضم حسيه جايعت بغذاد / )ابٍ انهُثى( كهُت انخشبُت نهعهىو انصشفت /قسى انفُضَاء 6102/كاوون االول /01,قبم في: 6102/تشريه االول/3استهم في : انخالصة بعًهُت صهش انًىاد االونُت وفق َسب يخخهفت نُسبت انسُهُُُىو Bi2(Te1-x Sex)3حى ححضُش سبائك انًشكب (x=0 , 0.1 ,0.3 ,0.5 ,0.7,0.9 and 1) . 10باسخخذاو حقُُت انخبخُش انحشاسٌ ححج ضغط فشاغ َصم انً هااالغشُت انشقُقت نهزا انًشكب حى ححضُش -5 torr) حُذ حى ) . .nm 30±450)بسًك ) 12nm/min)بًعذل حشسُب)حشسُب انًادة عهً قىاعذ صجاجُت َظُفت فٍ دسجت حشاسة انغشفت , ايا انخىاص انخشكُبُت XRF( باسخخذاو جهاص فهىسة االشعت انسُُُُت Bi ,Te and Seقذ حى انخأكذ يٍ َسب انًىاد األونُت ) باخخالف َسبت انسُهُُىو فُها بىاسطت جهاص حُىد االشعت انسُُُت Bi2(Te1-x Sex)3نهسبائك واالغشُت انشقُقت نًشكب XRD انشقُقت حى فحصها باسخعًال جهاص ايا انخىاص انسطحُت نالغشُتAFM وقذ وجذ اٌ اقطاس انحبُباث حضداد بضَادة َسبت انسُهُُُىو فُها وكزنك َضداد يعذل انخشىَت فُها اٌ قُاط حُىد االشعت انسُُُت وجذ اٌ انسبائك واالغشُت انشقُقت نها R حشكُب يخعذد انخبهىس رو حشكُب سذاسٍ وفسحت يجًىعت 3 m ( ٍوكزنك بُُج اٌ 015وكاَج انقًت انسائذة واالقىي ه ) حجى انبهىسَاث َضداد بضَادة َسبت انسُهُُُىو فٍ انًشكب . , انخبخُش انحشاسٌ, وخىاص ,اغشُت سقُقت: بضيىد حُهىساَذ , بضيىد سُهُاَذ, خىاص كهشو حشاسَت انكهمات انمفتاحية حشكُبُت .