Effect of Annealing on the Properties of Nanocrystalline CdS Thin Films Prepared by CBD Method

The CdS thin films were deposited on glass substrate by chemical bath deposition (CBD). The effect of annealing temperature on the morphological, structural, optical and electrical properties of the crystalline CdS films were investigated for different annealing temperature (as deposited, 300, 400 and 500 °C).The annealing time is 1 h. The materials have been prepared using simple aqueous solutions containing cadmium sulfate, as source of cadmium, and thiourea as source of sulfur and ammonium hydroxide as the complexing agent. The temperature of the bath was maintained at low temperature of 80 °C. The surface morphological properties studied by SEM and AFM respectively. The structural properties of CdS thin film was studied by X-ray diffraction. The optical parameter such as transmittance and energy band gap of the films with thermal annealing temperature was investigated by UV-Visible spectrophotometer. The variation of band gap values of CdS thin film samples were found to be in the range of 2.37 to 2.5 eV. Electrical resistivity measurements were carried out in four-probe Van Der Pauw geometry at room temperature by the Hall measurement. SEM image confirmed that film of smooth surface morphology

Properties Study of ZnS Thin Films Prepared by Spray Pyrolysis Method

Zinc sulfide (ZnS) is important II-VI semiconductors material for the development of various modern technologies and photovoltaic applications. ZnS thin film was prepared by using chemical spray pyrolysis technique. The starting solution is a mixture of 0.1 M zinc chloride as source of Zn and 0.05 M thiourea as source of S. The glass substrate temperature was varied in the range of 300 °C-400 °C to investigate the influence of substrate temperature on the structure, chemical composition, morphological and optical properties of ZnS films. The DRX analyses indicated that ZnS films have polycrystalline cubic structure with (111) preferential orientation and grain size varied from 25 to 60 nm, increasing with substrate temperature. The optical properties of these films have been studied in the wavelength range 300-2500 nm using UV-VIS spectro-photometer. The ZnS films has a band gap of 3.89 eV-3.96 eV

Properties Study of ZnS Thin Films Prepared by Spray Pyrolysis Method

Zinc sulfide (ZnS) is important II-VI semiconductors material for the development of various modern technologies and photovoltaic applications. ZnS thin film was prepared by using chemical spray pyrolysis technique. The starting solution is a mixture of 0.1 M zinc chloride as source of Zn and 0.05 M thiourea as source of S. The glass substrate temperature was varied in the range of 300 °C-400 °C to investigate the influence of substrate temperature on the structure, chemical composition, morphological and optical properties of ZnS films. The DRX analyses indicated that ZnS films have polycrystalline cubic structure with (111) preferential orientation and grain size varied from 25 to 60 nm, increasing with substrate temperature. The optical properties of these films have been studied in the wavelength range 300-2500 nm using UV-VIS spectro-photometer. The ZnS films has a band gap of 3.89 eV-3.96 eV

Compact and Highly Sensitive Bended Microwave Liquid Sensor Based on a Metamaterial Complementary Split-Ring Resonator

YesIn this paper, we present the design of a compact and highly sensitive microwave sensor based on a metamaterial complementary split-ring resonator (CSRR), for liquid characterization at microwave frequencies. The design consists of a two-port microstrip-fed rectangular patch resonating structure printed on a 20 × 28 mm2 Roger RO3035 substrate with a thickness of 0.75 mm, a relative permittivity of 3.5, and a loss tangent of 0.0015. A CSRR is etched on the ground plane for the purpose of sensor miniaturization. The investigated liquid sample is put in a capillary glass tube lying parallel to the surface of the sensor. The parallel placement of the liquid test tube makes the design twice as efficient as a normal one in terms of sensitivity and Q factor. By bending the proposed structure, further enhancements of the sensor design can be obtained. These changes result in a shift in the resonant frequency and Q factor of the sensor. Hence, we could improve the sensitivity 10-fold compared to the flat structure. Subsequently, two configurations of sensors were designed and tested using CST simulation software, validated using HFSS simulation software, and compared to structures available in the literature, obtaining good agreement. A prototype of the flat configuration was fabricated and experimentally tested. Simulation results were found to be in good agreement with the experiments. The proposed devices exhibit the advantage of exploring multiple rapid and easy measurements using different test tubes, making the measurement faster, easier, and more cost-effective; therefore, the proposed high-sensitivity sensors are ideal candidates for various sensing applications.This work was supported by the Moore4Medical project, funded within ECSEL JU in collaboration with the EU H2020 Framework Programme (H2020/2014–2020) under grant agreement H2020-ECSEL-2019-IA-876190, and the Fundação para a Ciência e Tecnologia (ECSEL/0006/2019). This project received funding in part from the DGRSDT (Direction Générale de la Recherche Scientifique et du Développement Technologique), MESRS (Ministry of Higher Education and Scientific Research), Algeria. This work was also supported by the General Directorate of Scientific Research and Technological Development (DGRSDT)–Ministry of Higher Education and Scientific Research (MESRS), Algeria, and funded by the FCT/MEC through national funds and, when applicable, co-financed by the ERDF, under the PT2020 Partnership Agreement under the UID/EEA/50008/2020 project

Optoelectronic characterization of CuInGa(S)2 thin films grown by spray pyrolysis for photovoltaic application

[EN] Copper-indium gallium disulfide (CIGS) is a good absorber for photovoltaic application. Thin films of CIGS were prepared by spray pyrolysis on glass substrates in the ambient atmosphere. The films were characterized by different techniques, such as structural, morphological, optical and electrical properties of CIGS films were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), spectrophotometer and Hall effect, respectively. After optimization, the deposited films structure, grain size, and crystallinity became more important with an increase of annealing time at 370 degrees C for 20 min. Transmission electron microscopy (TEM) analysis shows that the interface sheets are well crystallized and the inter planer distance are 0.25 nm, 0.28 nm, and 0.36 nm. The atomic force microscopy (AFM) observation shows that the grain size and roughness can be tolerated by optimizing the annealing time. The strong absorbance and low transmittance were observed for the prepared films with a suitable energy bandgap about 1.46 eV. The Hall effect measurement system examined that CIGS films exhibited optimal electrical properties, resistivity, carrier mobility, and carrier concentration which were determined to be 4.22 x 10(6) omega cm, 6.18 x 10(2) cm(2) V-1 S-1 and 4.22 x 10(6) cm(-3), respectively. The optoelectronic properties of CIGS material recommended being used for the photovoltaic application.Prof. Bouchaib HARTITI, The Senior Associate at ICTP, is very grateful to ICTP for permanent support. Prof. Mohamed Ebn Touhami, Director of the University Center for Analysis, Expertise, Transfer of Technology and Incubation, Kenitra, Morocco, is very grateful to CUA2TI for financial support. Thanks to Doctor Diogo M.F. Santos for the supervision of Amal Bouich's work during her research in CeFEMA research center. The authors also thank researchers from CeFEMA (IST-ULisboa, Portugal) and CUA2TI (FS-Kenitra Morocco) for their help.Bouich, A.; Hartiti, B.; Ullah, S.; Ullah, H.; Ebn Touhami, M.; Santos, DMF.; Marí, B. (2019). Optoelectronic characterization of CuInGa(S)2 thin films grown by spray pyrolysis for photovoltaic application. Applied Physics A. 125(8):1-9. https://doi.org/10.1007/s00339-019-2874-4S191258T. Feurer, P. Reinhard, E. Avancini, B. Bissig, J. Löckinger, P. Fuchs, S. Buecheler, Progress in thin film CIGS photovoltaics–Research and development, manufacturing, and applications. Prog. Photovolt. Res. Appl. 25(7), 645–667 (2017)A. Zegadi, M.A. Slifkin, M. Djamin, A.E. Hill, R.D. Tomlinson, A photoacoustic study of CuInxGa1− xSe2 alloys. Phys. Status Solidi (A) 133(2), 533–540 (1992)T.H. Sajeesh, A.R. Warrier, C.S. Kartha, K.P. Vijayakumar, Optimization of parameters of chemical spray pyrolysis technique to get n and p-type layers of SnS. Thin Solid Films 518(15), 4370–4374 (2010)J. Liu, D. Zhuang, H. Luan, M. Cao, M. Xie, X. Li, Preparation of Cu (In, Ga) Se2 thin film by sputtering from Cu (In, Ga) Se2 quaternary target. Progr. Nat. Sci. Mater. Int. 23(2), 133–138 (2013)M.I. Hossain, Fabrication and characterization of CIGS solar cells with In2 S3 buffer layer deposited by PVD technique. Chalcogenide Lett. 9(5), 185–191 (2012)M.A. Mughal, R. Engelken, R. Sharma, Progress in indium (III) sulfide (In2S3) buffer layer deposition techniques for CIS, CIGS, and CdTe-based thin film solar cells. Sol. Energy 120, 131–146 (2015)M. Powalla, M. Cemernjak, J. Eberhardt, F. Kessler, R. Kniese, H.D. Mohring, B. Dimmler, Large-area CIGS modules: Pilot line production and new developments. Sol. Energy Mater Sol. Cells 90(18–19), 3158–3164 (2006)M.E. Calixto, P.J. Sebastian, R.N. Bhattacharya, R. Noufi, Compositional and optoelectronic properties of CIS and CIGS thin films formed by electrodeposition. Sol. Energy Mater. Sol. Cells 59(1–2), 75–84 (1999)S. Jung, S. Ahn, J.H. Yun, J. Gwak, D. Kim, K. Yoon, Effects of Ga contents on properties of CIGS thin films and solar cells fabricated by co-evaporation technique. Curr. Appl. Phys. 10(4), 990–996 (2010)S. R. Ovshinsky, X. Deng, R. Young, U.S. Patent No. 5,231,047. Washington, DC: U.S. Patent and Trademark Office (1993).M. Kaelin, D. Rudmann, A.N. Tiwari, Low cost processing of CIGS thin film solar cells. Sol. Energy 77(6), 749–756 (2004)Fangdan Jiang, Jiayou Feng, Effect of temperature on selenization process of metallic Cu–In alloy precursors. Thin Solid Films 515(4), 1950–1955 (2006)S. Shirakata, Y. Kannaka, H. Hasegawa, T. Kariya, S. Isomura, Properties of Cu (In, Ga) Se2 thin films prepared by chemical spray pyrolysis. Jpn. J. Appl. Phys. 38(9R), 4997 (1999)Y.K. Kumar, G.S. Babu, P.U. Bhaskar, V.S. Raja, Effect of starting-solution pH on the growth of Cu2ZnSnS4 thin films deposited by spray pyrolysis. Phys. Status Solidi (A) 206(7), 1525–1530 (2009)M. Ajili, M. Castagné, N.K. Turki, Characteristics of CuIn1− xGaxS2 thin films synthesized by chemical spray pyrolysis. J. Lumin. 150, 1–7 (2014)B.J. Babu, S. Velumani, A. Kassiba, R. Asomoza, J.A. Chavez-Carvayar, J. Yi, Deposition and characterization of graded Cu (In1-xGax) Se2 thin films by spray pyrolysis. Mater. Chem. Phys. 162, 59–68 (2015)S.F. Varol, G. Babür, G. Çankaya, U. Kölemen, Synthesis of sol–gel derived nano-crystalline ZnO thin films as TCO window layer: effect of sol aging and boron. RSC Adv. 4(100), 56645–56653 (2014)J.A. Frantz, R.Y. Bekele, V.Q. Nguyen, J.S. Sanghera, A. Bruce, S.V. Frolov, I.D. Aggarwal, Cu (In, Ga) Se2 thin films and devices sputtered from a single target without additional selenization. Thin Solid Films 519(22), 7763–7765 (2011)C. Calderón, G. Gordillo, P. Bartolo-Pérez, F. Mesa, Effect of the deposition conditions on the optical, morphological and compositional properties of CuIn1− xGaxSe2 thin films prepared by a multistage process. Revista Mexicana de Física 53(7), 270–273 (2007)D. Schmid, M. Ruckh, F. Grunwald, H.W. Schock, Chalcopyrite/defect chalcopyrite heterojunctions on the basis of CuInSe2. J. Appl. Phys. 73(6), 2902–2909 (1993)U.C. Matur, S. Akyol, N. Baydoğan, H. Cimenoglu, The optical properties of CIGS thin films derived by sol-gel dip coating process at different withdrawal speed. Proc. Soc. Behav. Sci. 195, 1762–1767 (2015)A. Bouich, B. Hartiti, S. Ullah, M.E. Touhami, B. Mari, D.M.F. Santos, Investigation of the optical properties of CuIn (Se, S)2 thin films for photovoltaic application. Mater. Today Proc. 13, 663–669 (2019)K. Matsumura, T. Fujita, H. Itoh, D. Fujita, Characterization of carrier concentration in CIGS solar cells by scanning capacitance microscopy. Meas. Sci. Technol. 25(4), 044020 (2014)A. Bouich, B. Hartiti, S. Ullah, H. Ullah, M.E. Touhami, D.M.F. Santos, B. Mari, Experimental, theoretical, and numerical simulation of the performance of CuInxGa(1–x) S2 based solar cells. Optik 183, 137–147 (2019

Реалізація системи зонду Кельвіна для обробки поверхні напівпровідника

Знання електричних властивостей матеріалів неминуче в поверхневих технологіях, таких як мікротехнологія, корозія тощо. Що стосується поверхневих явищ, то робота виходу являє собою основну властивість. Вона була розроблена лордом Кельвіном і відповідає контактній різниці потенціалів між двома поверхнями матеріалів. У роботі збирання даних системи зонду Кельвіна (KPS) проводилося після послідовних випробувань в електронних обчисленнях і фізичних полях з метою отримання роботи виходу провідникових і напівпровідникових матеріалів. Ця система виявила велике значення управління напругою підтримки Vb для обчислення конденсатора, застосованого в структурі метал-діелектрикнапівпровідник (MIS) для вимірювання поверхневого потенціалу напівпровідників. Деякі проблеми були вирішені під час створення системи, і відповідна частота 50 Гц була належним чином відрегульована. Однак вольт-амперне перетворення в KPS не проводилося через нечутливість використаних підсилювачів. Щоб зрозуміти цю складність експериментального дослідження сигналу, ми використали обчислення за допомогою коду Фортран. Воно підтвердило, що сигнал зонда Кельвіна має дуже слабку амплітуду порядка піковольт. З іншого боку, завдяки іншим доступним вимірювальним приладам, чутливість яких значно нижча, ніж сам сигнал, ці результати виправдовують експериментальні кроки.The knowledge of the electrical properties of materials is inevitable in surface technologies, such as microtechnology, corrosion, etc. Concerning the surface phenomena, the work function represents the main property. It was developed by Lord Kelvin and it corresponds to the contact potential difference between two surfaces of materials. In this project, the data acquisition of Kelvin Probe System (KPS) was performed after sequential tests in electronic computing and physical fields in order to acquire the work function of conductor and semiconductor materials. This system has revealed the great importance of controlling the support voltage Vb calculating the capacitor applied to the Metal-Insulator-Semiconductor (MIS) structure in order to measure the surface potential of the semiconductors. Some problems were solved during the assembly of the system and the pertinent frequency of 50 Hz was suitably adjusted. However, the conversion of current-voltage was not carried out in KPS due to the insensitivity of the amplifiers on hand. To understand this difficulty in signal experimental study, we have used a calculation by a Fortran code. The latter has confirmed that the signal of Kelvin probe is a very weak amplitude of the order of pico-volts. Because of the available measuring devices whose sensitivity is much lower than the signal itself, on the other hand, these results justify the experimental steps

Розробка наночастинок фериту цинку міді: застосування в каталітичному вологому окисленні H2O2 фенолу

Ця робота стосується синтезу і характеристики змішаних оксидів металів та їх застосування як каталізаторів. Синтезований твердий розчин фериту Fe2Zn1 – xCuxO4. Чистота зразків була підтверджена рентгенівською дифракцією (XRD). Характеристики зразків отримували за допомогою інфрачервоної спектроскопії з використанням перетворення Фур'є (FTIR) та скануючої електронної мікроскопії (SEM). Уточнення параметрів решітки твердого розчину було розроблено з індексації основної сполуки NiFe2O4 у кубічній елементарній комірці просторової групи Fd3m. Тенденція ліній дифракції показує, що структура була добре кристалізована, і справді утворився повноцінний твердий розчин кубічної симетрії. Мікрофотографія SEM виявляє, що зразки представлені у вигляді кристалітів нанометрового розміру; зразки представлені у вигляді фрагментів різної величини в суміші Cu-Zn. Результати показують нанометровий розмір зерен, що змінюється між 90 і 130 нм. Ці нещодавно розроблені матеріали застосовуються як каталізатори для неоднорідної реакції окислення фенольних сполук; предмет дослідження за наявності перекису водню. Продукти деструкції аналізували високоефективною рідинною хроматографією. Отримані результати показали потужний каталітичний характер цих оксидів до повного розкладання фенолу.This work deals with the synthesis, characterization of mixed oxides of metals and their applications as catalysts. The synthesized ferrite solid solution of formula Fe2Zn1 – xCuxO4 has been prepared from ground frost. The purity of the samples has been verified by X-Ray Diffraction (XRD). The characterizations of samples have been carried out using Fourier Transform InfraRed Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Refinement of lattice parameters of the solid solution has been elaborated from the basic compound NiFe2O4 indexing in a cubic unit cell of space group Fd3m. The trend of the diffraction lines shows that the structure was well crystallized, and there indeed a complete solid solution of cubic symmetry was formed. The SEM micrograph reveals that the samples are presented in the form of nanometer sized crystallites; the samples are in the form of fragments of different sizes in the Cu-Zn mixture. The results show the nanometric size of the grains varying between 90 and 130 nm. These newly elaborated materials have been applied as catalysts for heterogeneous reaction of oxidation of phenolic compounds; subject of investigations in the presence of hydrogen peroxide. The degradation products were analyzed by High Performance Liquid Phase Chromatography (HPLC). The obtained results showed powerful catalytic character of these oxides to completely degrade phenol

Вплив додавання Fe на структурні та оптоелектронні властивості тонких плівок ZnO p/n типу, нанесених методом центрифугування

У роботі повідомляється про вплив включення Fe на структурні та оптоелектронні властивості тонких плівок ZnO, отриманих методом центрифугування. Номінальне співвідношення Fe/Zn у розчині становило 7 %. Рентгенограми плівок показали, що леговане включення призводить до істотних змін структурних характеристик плівок ZnO. Усі плівки мають полікристалічну структуру з переважним зростанням вздовж площини (002) плівки ZnO. Розмір кристалітів був розрахований за відомою формулою Шеррера і виявився в діапазоні 22-17 нм. Найбільше середнє значення оптичного пропускання у видимій області спектру належало плівці ZnO, легованій Fe. Результати Раманівського розсіювання підтвердили спостереження методів XRD та УФ-спектроскопії появою цих місць на ділянках Zn+2. Ці результати пояснюються теоретично і порівнюються з тими, про які повідомляється іншими дослідниками. Результати Холівських вимірювань тонких плівок ZnO та ZnO:Fe виявляють високу концентрацію електронів приблизно 1016 см – 3 та їх низьку рухливість 2.6 см2/Вс. Усі вирощені зразки демонструють неоднозначний тип провідності носіїв (p- або n-тип) в автоматичних Холівських вимірюваннях Ван-дер Поу. Аналогічний результат спостерігався раніше іншими групами у плівках ZnO, легованих Li та As. Однак, охарактеризувавши зразки рентгено-електронною спектроскопією (XPS), ми продемонстрували, що неоднозначний n-тип носіїв у наших плівках ZnO не є внутрішньою поведінкою зразків, а обумовлений стійким ефектом фотопровідності в ZnO.This paper reports the effect of Fe incorporation on structural and electro-optical properties of ZnO thin films prepared by spin coating techniques. The Fe/Zn nominal volume ratio was 7 % in the solution. X-ray diffraction patterns of the films showed that doped incorporation leads to substantial changes in the structural characteristics of ZnO films. All the films have polycrystalline structure, with a preferential growth along the ZnO (002) plane. The crystallite size was calculated using a well-known Scherrer’s formula and found to be in the range of 22-17 nm. The highest average optical transmittance value in the visible region was belonging to the Fe doped ZnO film. The results of the Raman scattering confirmed the observations of XRD and UV-Vis analysis techniques by the appearance of these occupancies at Zn+2 sites. These results are explained theoretically and are compared with those reported by other workers. The results of Hall measurement of ZnO and ZnO:Fe thin films reveal a high electron concentration around 1016 cm – 3 and low mobility 2.6 cm2/Vs. All as-grown samples show ambiguous carrier conductivity type (p-type and ntype) in the automatic Van der Pauw Hall measurement. A similar result has been observed in Li-doped ZnO and in As-doped ZnO films by other groups before. However, by characterizing our samples whit XPS, we have demonstrated that the ambiguous carrier type n in intended our ZnO films is not intrinsic behavior of the samples. It is due to the persistent photoconductivity effect in ZnO

Influence of Gaussian Hill on Concentration of Solid Particles in Suspension Inside Turbulent Boudary Layer

AbstractThe soil erosion is a major problem that affects the agriculture, climate and health. It is therefore necessary to understand the phenomena that are its wheels in order to either predict or limit it. One of the main problem of this kind of study is the presence of high particle concentration that restricts measurements of either particle concentration or carrier flow rate. In so numerical simulations are essential for detailed studies. Nevertheless these numerical models have to be performant enough and validated with situations that if they are not realistic are representative of phenomena involved. So here we focused on the problem of the possibility of trapping the solid particles in the recirculation zones. We have reproduced in laboratory a configuration representative of sites with enough steep hills to generate recirculation zones during saltation regimes.Measurements have been made of the dispersion of solid particles released from a rectangular area flushed at the ground of a flat plate on which evolved a turbulent boundary layer. The originality here is that it is flushed at the ground and push up the particles to continuously feed the ground at the same mean rate as the mean local erosion rate. One or more Gaussian hills were disposed transversally to the flow downstream the solid particle injection. Various Reynolds number where chosen to caracterise take-off regimes and recirculation regime behind the Gaussian hill(s). One optical system combined with CMOS camera is used successively to measure the velocity of career fluid or solid particles by PIV. Digital Image treatment is used to separate fluid seeding from solid particle images. Supplementary comparison was done to compare velocity field of the career flow for smooth and rough floor only for kinematic around the hill(s).In this paper, in a first part we will present kinematic caracteristics of the flow whereas in a second part of this work, the data will provide some concentration profiles of solid particles. The results presented concerning the velocity and concentration field are related to streamwise vertical planes at the center of the wind tunnel at successive longitudinal positions. For velocity field we will report different regimes for smooth and rough plate. Only one regime will be presented for solid particles. We present in a first part the kinematic study and in the second part results on the concentrations of solid particles

Першопринципне дослідження рідкоземельних мононитридів ScN і YN під тиском

Ми повідомляємо про дослідження фаз високого тиску сполук YN та ScN, використовуючи останню версію методу FPLMTO, який забезпечує точну обробку міжвузлових областей. Наближення локальної густини (LDA) застосовували для обмінної та кореляційної функціональної густини енергії. Приведено розрахунки параметрів решітки, об'ємного модуля та його перших похідних у різних структурах. Ми виявили, що при стисненні ScN перетворюється із структури типу NaCl (B1) у тип β-Sn (A5) під тиском близько 301,3 ГПа з прямою забороненою зоною приблизно рівною 0,108 еВ. Цей перехід від B1 до A5 відбувається за нижчого тиску, ніж добре відомий перехід структури типу NaCl (B1) у структуру типу CsCl (B2) (виявлене в статті значення складає 412 ГПа). Наші розрахунки також показують, що YN перетворюється з B1 на B2 під тиском близько 198,5 ГПа.We report the study of high-pressure phases of YN and ScN compounds, using a recent version of the full potential linear muffin-tin orbital (FPLMTO) method, which enables an accurate treatment of the interstitial regions. The local density approximation (LDA) was used for the exchange and correlation energy density functional. Calculations are given for lattice parameters, bulk modulus and its first derivatives in different structures. Under compression, we found that ScN transforms from NaCl-type structure (B1) to Beta-Sn-type (A5) at a pressure of around 301.3 GPa, with a direct energy gap at Γ of about 0.108 eV. This transition B1 to A5 takes place at a lower pressure than the well-known transition NaCl-type structure (B1) to CsCl-type structure (B2) (found here to be 412 GPa). Our calculations also show that YN transforms from B1 to B2 at a pressure of around 198.5 GPa