Microsoft Word - 273-278 273 | Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 Fabrication and Characterization CdO:In/Si Photovoltaic Solar Cell Prepard By Thermal Evaporation Mohammed H.Mustafa Dept.of physics/ College of Education for Pure Scince(Ibn Al-Haitham)/ University of Baghdad Received in :5June 2014 Accepted in :8September2014 Abstract In this work, CdO:In/Si heterojunction solar cell has been made by vacuum evaporation of cadmium oxide doped with 1% of indium thin film onto glass and silicon substrates with rate deposition (3.9A/sec) and thickness(≈250nm). XRD was investigated, the transmission was determined in range (300-1100)nm and the direct band gap energy is 2.43 eV, I-V characterization of the cell under illumination was investigated , the cell shows an open circuit voltage (Voc) of 0.6 Volt, a short circuit current density (Jsc) of 12.8 mA/cm2, a fill factor (F.F) of 0.66, and a conversion efficiency (η) of 5.2%. Key Words: Fabrication, Characterization, Photovoltaic, Solar, Cell . 274 | Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 Introduction Researchers have focused on transparent conductive oxide (TCO) materials because of their applications, specifically those in the field of optoelectronic devices [1,2] such as photodiodes, phototransistors , photovoltaic cells [3], transparent electrodes [4], liquid crystal displays, IR detectors and antireflecting coatings [5],solar cells[6] and sensors [7]. There are several methods developed for the synthesis of CdO films such as spray pyrolysis , sputtering , chemical bath deposition (CBD) , pulsed laser deposition and thermal evaporation technique. The effect of doping various elements such as Sn, In, F, Cu and Ga on the physical properties of CdO thin films has already been reported.Doping increases its free electron concentration and electrical conductivity. Indium has been used as a suitable dopant for other transparent conducting films to increase the concentration of conduction electrons and improve the electrical conductivity, but there were few studies about In-doped CdO (In-CdO) films[8]. The aim of this paper is to present the results of the fabrication of n-CdO:In/p-Si heterojunction solar cell made by vacuum evaporating technique. Experimental Work Two types of substrates were used in this study. Glass slide which is used to study the structural and optical properties of CdO:In films, and p-type silicon wafer substrate with crystal orientation(111). The glass substrates were cleaned by using detergent with water to remove any oil or dust that might be attached to the surface of substrate and then they were placed under tap water and rubbing gently for 15 minutes. Then they were placed in a clean beaker containing distilled water and then rinsed in ultrasonic for 15 minutes. After that the distilled water with pure alcohol solution which reacts with contamination such as grease and some oxide. Substrates of p-type single crystal Si wafers of resistivity 2 ohm-cm and orientation (111) were used in the present study. After scribing these wafers into small pieces (typically 0.8cm x 0.8cm in size), with one surface polished with 2HF: 3HNO3: 3CH3COOH mixture (3:5:3) were cleaned ultrasonically by dipping in distilled water, acetone and isopropyl alcohol alternately. After cleaning, the samples were oxidized in dry oxygen. [9]. A specific weight from Cadmium oxide must be taken and put it in a special evaporation molybdenum boat, take (1%) from this weight from Indium and put it in other molybdenum boat. The films of CdO:In were prepared by thermal co- evaporation in vacuum of the order of 10-5 torr, the rate of evaporation was ≈3.9A/sec, onto clean silicon mirror-like side substrates at room temperature (~300K). The average thicknesses of the deposits were determined by microbalance method. The maximum error in the determination of thickness was of the order of 10% estimated for the thinnest films (CdO:In/Si films of thickness 250 nm).Ohmic contacts of a study on the electrical properties CdO:In/Si heterojunction aluminum [10] were evaporated on the silicon side and CdO:In/Si side. Result and Discussion Figure (1) and table(1) show the XRD spectra obtained at room temperature for CdO:In film. The XRD pattern for Cadmium oxide doped with Indium film at room temperature reveals exhibit a prominent reflection angles at 2θ0=33.02, 2θ0=38.22 and 2θ0=55.28. And the crystal lattice is cubic; these XRD peaks are shown to be the (111),(200) and (220). The Figure (2) refers to transmission of CdO:In film in the range between (300-1100)nm. 275 | Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 The optical energy gap values (Eg) for CdO:In films have been determined. A plot of (hν)2 versus photon energy for CdO:In film is shown in Fig.(3). The plot is linear indicating as direct band gap nature of the film. Extrapolation of the line to the photon energy axis gives the band gap. The value of the optical energy gap for Cadmium oxide doped with Indium film is equal to (2.43 eV). This result agrees approximately with the result reported by Khalid [11]. Figure (4) shows the I-V characteristics of n-CdO:p-Si solar cell under illumination. The short circuit current ( Isc ), the open circuit voltage (Voc) , fill factor (F.F) and the photovoltaic conversion efficiency(η) have been determined. The fill factor given by the relation[12,13]. scocmm IVIVFF . x 100% ……………… (1) Where( Im ) and( Vm ) are the current and voltage corresponding to the maximum power point.the photovoltaic conversion efficiency (η) is given by: 0 0100.  inocscinm pVIFFpp ……… (2) Where pm is the area of the maximum power rectangle, and pin is the incident power [12,13]. In the present study, the n-CdO:In/p-Si solar cell has an open-circuit voltage (Voc) of 0.6 Volt, a short-circuit current density (Jsc) of 12.8 mA/cm2, a maximum voltage (Vmax) of 0.51 Volt, and a maximum current (Jmax) of 10.2 mA/cm2, fill factor (F.F) of 0.667, and the value of the conversion efficiency (η) for n-CdO:In/p-Si solar cell is equal to(5.2%). These results are not coincident with Ramis [8] because of the different method and Conditions of preparation. Conclusion A CdO:In thin film was successfully deposited on a p-Si substrate to yield a solar cell via thermal evaporation in a vacuum. The XRD pattern showed that the thin film was polycrystalline in nature with a cubic structure. The direct band gap energy of the CdO:In thin film was 2.43 eV. the solar cell conversion efficiency (n-CdO:In/p-Si) was 5.2% under a 100 mW/cm2 illumination condition using thermal evaporation in a vacuum. Reference 1. Goldsmith ,S. (2006) Filtered vacuum arc deposition of undoped and doped ZnO thin films: Electrical, optical, and structural properties, Surf. Coat. Technol. 201, 3993. 2. Balu ,A. R.; Nagarethinam,V.S.; Suganya . M.; Arunkumar, N.and Selvan,G.,(2012) , Effect of the solution concentration on the strurtural, optical and electrical properties of SILAR deposited CdO thin films, Journal of Electron Devices 12, 739 . 3. Champness ,C.H; Ghoneim, K; Chen, J.K. et al,(1985) Optimization of CdO layer in a Se- CdO Photovoltaic cell. Can. J. Phys; 63. 4. Benko , F.A.; Koffyberg, F.P. et al,(1986), Quantum efficiency and optical transitions of CdO photoanodes, Solid State Commun; 57: 901. 5. Ocampo, IM ; Ferandez , AM; Sabastian , PJ et al ,(1993), Low resistivity transparent conducting CdO thin films deposited by DC reactive magnetron sputtering at room temperature.Semicond.Sci. Technol; 8: 750. 6. Vigil,O; Vaillant ,L; Cruz, F et al, (2000) , Properties of transparent conducting oxides formed from CdO alloyed with In2O3, Thin Solid Films; 53: 361. 276 | Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 7.Ortega, M .;Sontana ,G. and Acevedo ,A.M.,(1999),Optoelectronic properties of Cdo-Si heterojunction;294-295. 8.Ramis,A. Al-Anssari ;Nadir,F.,Habubi;Jinan Ali Abd,(2013),Fabrication and characterization of n- CdO:In/p-Si thin film solar cell. Journal of Electron Devices, 17, 1457-1464. 9.Ponpon, J. P; and Siffert, P. (1978),Role of oxygen in the mechanism of formatting of Schottky diodes, Mukolu J. Appl. Phys., 49 (12), 6004. 10.Oberafo,A.A. etal,(1994),The Nature of Some Contacts (Al, In, Ge, Sb and Bi) to Selenium Films, Tr. J. of Physics, 18, 727-733. 11.Khalid,Z.,Yahiya,(2008),Fabrication and characterization of high efficient CdO/Si photovoltaic solar cells. Journal of Al-Nahrain University Vol.11(1), 56-58 . 12. Zaien, M. ; Ahmed, N. M.; and Hassan, Z. (2012), Superlattices and Microstructures, 52, 800-806. 13. Alfa, B.; Tsepav, M. T.; Njinga , R. L; and Abdulrauf, I. (2012), Applied Physics Research, 4 ; 48-56. Table No. (1) X-ray diffraction data for CdO:In thin films ASTM 2ϴ0 Experimental Value 2ϴ0 (h k l) Plane 33.00 33.02 (111) 38.28 38.22 (200) 55.25 55.28 (220) Figure No. (1): XRD of CdO:In thin film on glass substrate 277 | Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 Figure No. (2): The optical transmission (T%) as a function of wavelength for CdO:In film Figure No. (3): The energy gap of CdO:In film Figure No. (4): Current density-Voltage curves of the (n-CdO:In/p-Si) solar cell 278 | Physics 2014) عام 3العدد ( 27مجلة إبن الھيثم للعلوم الصرفة و التطبيقية المجلد Ibn Al-Haitham Jour. for Pure & Appl. Sci. Vol. 27 (3) 2014 طة اسالمحضرة بو CdO:In/Si تصنيع وخصائص الخلية الشمسية الفولتائية التبخير الحراري محمد حامد مصطفى جامعة بغداد /)ابن الهيثم(كلية التربية للعلوم الصرفة /قسم الفيزياء 2014ايلول8قبل البحث 2014ايار5استلم البحث الخالصة بـ المشوب الكادميوم أغشية بتبخير ،وذلك CdO:In/Siنوع ھجينة سيةشم خاليا في ھذا البحث، صنعت درس . (250nm≈)وسمك 3.9A/sec)( ترسيب بمعدل و سليكونية و زجاجية قواعد على انديوم ) 1%( فجوة حسبت , nm)(300-1100للمدى النفاذية طيف ومن األشعة السينية، حيود طةاسبو للغشاء البلوري التركيب أداء خليةلل ان فتبين اإلضاءة حالة في جھد -قياسات تيارواجريت ، eV( 2.43)وكانت قيمتھا المباشرة الطاقة ocV() 0.6 (الدائرة المفتوحة ) وان فولتية /scJ( )2cm 12.8 mA ( ةريالقص دائرة ال تياركثافة إن فولتائي جيـــد , اذ Volt ( وبكفاءة تحويل(η) (5.2%) (0.66)وعامل ملء (F.F). .:تصنيع,خصائص,خلية,الشمسية,الفولتائيةالكلمات المفتاحية