Fluorine-doped ZnO (FZO) thin films were deposited onto glass by the spray pyrolysis process, usi... more Fluorine-doped ZnO (FZO) thin films were deposited onto glass by the spray pyrolysis process, using zinc acetate and NH4F as precursors. The role of F/Zn atomic ratio, in the starting solution, and the substrate temperature were investigated and the optimum deposition conditions have been outlined. The X-ray diffraction analyses of the films show that there is incorporation of F atoms
The growth and structural properties of Sn x S y (SnS 2 , Sn 2 S 3 ) prepared by the plasma-enhan... more The growth and structural properties of Sn x S y (SnS 2 , Sn 2 S 3 ) prepared by the plasma-enhanced chemical vapor deposition process have been studied systematically. Sn x S y thin films were prepared by the decomposition of H 2 S and SnCl 4 vapors mixture in a capacitively coupled 13.56 MHz radio frequency glow discharge chamber with a radially symmetric flow pattern. Hydrogen was used as a diluent gas and for removing chlorine radicals generated by the SnCl 4 decomposition. The deposition pressure, substrate temperature, and plasma power density were kept constant at 50 mTorr, 150°C, and 25 mW/cm 2 , respectively. The relative concentration of the precursor materials, g, defined as the ratio of tin chloride mass flow rate to the sum of tin chloride and hydrogen sulfide mass flow rates, was varied from 0 to 1.0. A total mass flow rate of 25 standard cubic centimeter per minute for the precursor materials and the diluent gas was used in all the cases. It was found that (i) For g 0.6, the deposited films contain a mixture of hexagonal SnS 2 and orthorhombic Sn 2 S 3 compounds; and (iii) For g close to 0.5, the deposited material has only the Sn 2 S 3 compound. In all the samples, the size of the crystallites and the lattice parameters were estimated from the width of the X-ray diffraction peaks and the interplanar distances. It was found that the chemical composition, the crystallinity, and the preferential growth of the deposited material are well controlled by adjusting the value of g.
2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC), 2018
Tin sulfide (SnS) thin films have attracted attention for its great potential for photovoltaic ap... more Tin sulfide (SnS) thin films have attracted attention for its great potential for photovoltaic applications as absorber material due to its optical properties, stability and structural characteristics, however, the efficiency of photovoltaic structure based undoped SnS hasbeen found to be low due to their low conductivity. In this work, we analyzed the influence doping of copper (Cu) on SnS (SnS:Cu) thin films and how are affected its structural and optoelectronic properties. The SnS:Cu thin films were obtained by ultrasonic spray pyrolysis technical at different Cu concentrations (0, 2, 5 and 10 %), controlling the other deposit parameters. X-Ray Diffraction studies show changes in the structure as increasing the level of doped going from being orthorhombic to cubic. We used transmittance and reflectance versus wavelengthmeasurements to determine the energy band gap. We found an increment in the band gap when the doping concentration was increased. From Hall-Van der Pauw effect, th...
β-In2S3 thin films, deposited by spray pyrolysis, were treated in N2 and air plasmas at 240 and 4... more β-In2S3 thin films, deposited by spray pyrolysis, were treated in N2 and air plasmas at 240 and 400 Pa. X-ray diffraction, SEM, and EDS analysis, and optical and electrical studies have been used to characterize the as-prepared and plasma treated thin films. The post-deposition plasma treatments affect the morphology and the optoelectronic properties of the In2S3 thin films. The In2S3 thin films treated with N2 plasma at 240 Pa showed an optical band gap, Eg, of 2.16 eV and an electrical conductivity of 2 × 10− 2 (Ω cm)− 1.
Heterojunction based on Sn–S compounds, SnS and SnS2, have been prepared by plasma-enhanced chemi... more Heterojunction based on Sn–S compounds, SnS and SnS2, have been prepared by plasma-enhanced chemical vapor deposition (PECVD). The semiconductor materials SnS and SnS2 were obtained by the decomposition of the gas precursors SnCl4 and H2S in a capacitive-coupled RF plasma-deposition chamber. Corning glass with a transparent conductor oxide (TCO) thin film was used as substrate. The structure of the diode was glass/TCO/n-type SnS2/p-type SnS/Al. The contact between the n-type and p-type Sn–S compounds was found to be rectifying. The estimate reverse saturation density current was 1.2×10−5 A/cm2. The ratio of forward-to-reverse current exceeded 300 within the range of applied voltages of −1.0 to 1.0 V and the estimated diode factor was 2.7. A photovoltaic effect was observed under illumination giving an open circuit voltage of 0.35 V and a small short circuit current density with a value of 1.5 mA/cm2.
Tin Selenide films were deposited by ultrasonic spray pyrolysis (USP) technique onto glass substr... more Tin Selenide films were deposited by ultrasonic spray pyrolysis (USP) technique onto glass substrates. 1, 1-dimethyl-2- Selenourea and SnCl2 were used as precursors of Se and Sn respectively. The X-ray technique shows that the deposited film is of a crystalline nature, identifying the SnSe compound, SnSe2 and SnO2 crystals. The obtained thin films were annealed at 300°C in an H2 atmosphere for 30 minutes to improve the purity of SnSe material. The XRD of the annealed films shows almost no signs of SnSe2 crystals. The measured value of the energy band gap (Eg) of the deposited SnSe films decreases after annealing treatment, from 1.23 eV to 1.09 eV. Seebeck effect showed p-type electrical conductivity in both films and Hall effect show almost no changes in the density of carrier charges and conductivity after annealing the samples. The fabricated devices show the photovoltaic effect with different values depending on the materials used.
This paper presents the visual defects and performance degradation rates of crystalline silicon p... more This paper presents the visual defects and performance degradation rates of crystalline silicon photovoltaic (PV) modules exposed in two different climatic conditions (Hot-Humid and Temperate) of Mexico between 10 and 25 years. An extensive evaluation of these modules was performed using different visual, optical and electrical tools including 86-point visual inspection, electroluminescence imaging, infrared imaging, module-level visible-near IR reflectance and current-voltage measurements. The dominant visual defects were determined to be encapsulant discoloration, encapsulant delamination and cell metallization corrosion. The average annual power degradation rate was determined to be between 1.4% and 1.5% for all the modules surveyed.
Indium sulfide (In2S3) thin films have been prepared by the spray pyrolysis (SP) technique using ... more Indium sulfide (In2S3) thin films have been prepared by the spray pyrolysis (SP) technique using indium acetate and N-N dimethyl thiourea as precursor compounds. Samples prepared at different temperatures and atomic ratio of In to S in the starting solution, (In/S)sol, have been characterized using several techniques. X-ray diffraction studies have shown that the preparation temperature (Tp) affects the crystallinity of the deposited materials as well as the optoelectronic properties. For (In/S)sol=1/8, the optical band gap (Eg) increases from 2.2 up to 2.67 eV when Tp increases from 250 up to 450 °C. For (In/S)sol=1 and Tp=450 °C, the deposited material shows n-type electrical conductivity with a dark value of 1 (Ωcm)−1, and Eg=2.04 eV. The In2S3 thin films prepared under these conditions have a big potential use as a window material for photovoltaic heterojunction devices.
In this work, we report on the elaboration of SnO2 and SnO2:Ag thin films (∼200 nm in thickness) ... more In this work, we report on the elaboration of SnO2 and SnO2:Ag thin films (∼200 nm in thickness) obtained by heat-treatment in oxygen of Sn and Sn:Ag thin films deposited by vacuum evaporation on alumina substrates. A simple and very cheap procedure was used to dope the SnO2 films with Ag. Preliminary results on the sensing properties of these films are presented. Films are able to detect selectively the presence of C3H8 in the LP-gas domestic mixture. Doping with Ag allows reductions in the optimal operation temperature of the SnO2 sensors by 100°C. This a very important result when detecting such a highly explosive gas.
The generation of electric power for supplying the populations of large cities is effected at an ... more The generation of electric power for supplying the populations of large cities is effected at an elevated cost, given that this cost does not include solely the price of generating the electric power itself, i.e., production, storage, labor, maintenance of installations, distribution, etc., but, in addition, bears the associated costs of damage to the environment due to the production of residual pollutants, and the consequent damage to the health of humans, and to the flora and fauna.
In a recent work we reported that chemically deposited intrinsic CdS thin films can be converted ... more In a recent work we reported that chemically deposited intrinsic CdS thin films can be converted into n-type with an electrical conductivity of 0268-1242/11/7/021/img1 by solid state diffusion of indium at temperatures of 0268-1242/11/7/021/img2 from a thin film of indium deposited by thermal evaporation on the CdS surface. In the present study, we report on the enhancement of grain size
Fluorine-doped ZnO (FZO) thin films were deposited onto glass by the spray pyrolysis process, usi... more Fluorine-doped ZnO (FZO) thin films were deposited onto glass by the spray pyrolysis process, using zinc acetate and NH4F as precursors. The role of F/Zn atomic ratio, in the starting solution, and the substrate temperature were investigated and the optimum deposition conditions have been outlined. The X-ray diffraction analyses of the films show that there is incorporation of F atoms
The growth and structural properties of Sn x S y (SnS 2 , Sn 2 S 3 ) prepared by the plasma-enhan... more The growth and structural properties of Sn x S y (SnS 2 , Sn 2 S 3 ) prepared by the plasma-enhanced chemical vapor deposition process have been studied systematically. Sn x S y thin films were prepared by the decomposition of H 2 S and SnCl 4 vapors mixture in a capacitively coupled 13.56 MHz radio frequency glow discharge chamber with a radially symmetric flow pattern. Hydrogen was used as a diluent gas and for removing chlorine radicals generated by the SnCl 4 decomposition. The deposition pressure, substrate temperature, and plasma power density were kept constant at 50 mTorr, 150°C, and 25 mW/cm 2 , respectively. The relative concentration of the precursor materials, g, defined as the ratio of tin chloride mass flow rate to the sum of tin chloride and hydrogen sulfide mass flow rates, was varied from 0 to 1.0. A total mass flow rate of 25 standard cubic centimeter per minute for the precursor materials and the diluent gas was used in all the cases. It was found that (i) For g 0.6, the deposited films contain a mixture of hexagonal SnS 2 and orthorhombic Sn 2 S 3 compounds; and (iii) For g close to 0.5, the deposited material has only the Sn 2 S 3 compound. In all the samples, the size of the crystallites and the lattice parameters were estimated from the width of the X-ray diffraction peaks and the interplanar distances. It was found that the chemical composition, the crystallinity, and the preferential growth of the deposited material are well controlled by adjusting the value of g.
2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC), 2018
Tin sulfide (SnS) thin films have attracted attention for its great potential for photovoltaic ap... more Tin sulfide (SnS) thin films have attracted attention for its great potential for photovoltaic applications as absorber material due to its optical properties, stability and structural characteristics, however, the efficiency of photovoltaic structure based undoped SnS hasbeen found to be low due to their low conductivity. In this work, we analyzed the influence doping of copper (Cu) on SnS (SnS:Cu) thin films and how are affected its structural and optoelectronic properties. The SnS:Cu thin films were obtained by ultrasonic spray pyrolysis technical at different Cu concentrations (0, 2, 5 and 10 %), controlling the other deposit parameters. X-Ray Diffraction studies show changes in the structure as increasing the level of doped going from being orthorhombic to cubic. We used transmittance and reflectance versus wavelengthmeasurements to determine the energy band gap. We found an increment in the band gap when the doping concentration was increased. From Hall-Van der Pauw effect, th...
β-In2S3 thin films, deposited by spray pyrolysis, were treated in N2 and air plasmas at 240 and 4... more β-In2S3 thin films, deposited by spray pyrolysis, were treated in N2 and air plasmas at 240 and 400 Pa. X-ray diffraction, SEM, and EDS analysis, and optical and electrical studies have been used to characterize the as-prepared and plasma treated thin films. The post-deposition plasma treatments affect the morphology and the optoelectronic properties of the In2S3 thin films. The In2S3 thin films treated with N2 plasma at 240 Pa showed an optical band gap, Eg, of 2.16 eV and an electrical conductivity of 2 × 10− 2 (Ω cm)− 1.
Heterojunction based on Sn–S compounds, SnS and SnS2, have been prepared by plasma-enhanced chemi... more Heterojunction based on Sn–S compounds, SnS and SnS2, have been prepared by plasma-enhanced chemical vapor deposition (PECVD). The semiconductor materials SnS and SnS2 were obtained by the decomposition of the gas precursors SnCl4 and H2S in a capacitive-coupled RF plasma-deposition chamber. Corning glass with a transparent conductor oxide (TCO) thin film was used as substrate. The structure of the diode was glass/TCO/n-type SnS2/p-type SnS/Al. The contact between the n-type and p-type Sn–S compounds was found to be rectifying. The estimate reverse saturation density current was 1.2×10−5 A/cm2. The ratio of forward-to-reverse current exceeded 300 within the range of applied voltages of −1.0 to 1.0 V and the estimated diode factor was 2.7. A photovoltaic effect was observed under illumination giving an open circuit voltage of 0.35 V and a small short circuit current density with a value of 1.5 mA/cm2.
Tin Selenide films were deposited by ultrasonic spray pyrolysis (USP) technique onto glass substr... more Tin Selenide films were deposited by ultrasonic spray pyrolysis (USP) technique onto glass substrates. 1, 1-dimethyl-2- Selenourea and SnCl2 were used as precursors of Se and Sn respectively. The X-ray technique shows that the deposited film is of a crystalline nature, identifying the SnSe compound, SnSe2 and SnO2 crystals. The obtained thin films were annealed at 300°C in an H2 atmosphere for 30 minutes to improve the purity of SnSe material. The XRD of the annealed films shows almost no signs of SnSe2 crystals. The measured value of the energy band gap (Eg) of the deposited SnSe films decreases after annealing treatment, from 1.23 eV to 1.09 eV. Seebeck effect showed p-type electrical conductivity in both films and Hall effect show almost no changes in the density of carrier charges and conductivity after annealing the samples. The fabricated devices show the photovoltaic effect with different values depending on the materials used.
This paper presents the visual defects and performance degradation rates of crystalline silicon p... more This paper presents the visual defects and performance degradation rates of crystalline silicon photovoltaic (PV) modules exposed in two different climatic conditions (Hot-Humid and Temperate) of Mexico between 10 and 25 years. An extensive evaluation of these modules was performed using different visual, optical and electrical tools including 86-point visual inspection, electroluminescence imaging, infrared imaging, module-level visible-near IR reflectance and current-voltage measurements. The dominant visual defects were determined to be encapsulant discoloration, encapsulant delamination and cell metallization corrosion. The average annual power degradation rate was determined to be between 1.4% and 1.5% for all the modules surveyed.
Indium sulfide (In2S3) thin films have been prepared by the spray pyrolysis (SP) technique using ... more Indium sulfide (In2S3) thin films have been prepared by the spray pyrolysis (SP) technique using indium acetate and N-N dimethyl thiourea as precursor compounds. Samples prepared at different temperatures and atomic ratio of In to S in the starting solution, (In/S)sol, have been characterized using several techniques. X-ray diffraction studies have shown that the preparation temperature (Tp) affects the crystallinity of the deposited materials as well as the optoelectronic properties. For (In/S)sol=1/8, the optical band gap (Eg) increases from 2.2 up to 2.67 eV when Tp increases from 250 up to 450 °C. For (In/S)sol=1 and Tp=450 °C, the deposited material shows n-type electrical conductivity with a dark value of 1 (Ωcm)−1, and Eg=2.04 eV. The In2S3 thin films prepared under these conditions have a big potential use as a window material for photovoltaic heterojunction devices.
In this work, we report on the elaboration of SnO2 and SnO2:Ag thin films (∼200 nm in thickness) ... more In this work, we report on the elaboration of SnO2 and SnO2:Ag thin films (∼200 nm in thickness) obtained by heat-treatment in oxygen of Sn and Sn:Ag thin films deposited by vacuum evaporation on alumina substrates. A simple and very cheap procedure was used to dope the SnO2 films with Ag. Preliminary results on the sensing properties of these films are presented. Films are able to detect selectively the presence of C3H8 in the LP-gas domestic mixture. Doping with Ag allows reductions in the optimal operation temperature of the SnO2 sensors by 100°C. This a very important result when detecting such a highly explosive gas.
The generation of electric power for supplying the populations of large cities is effected at an ... more The generation of electric power for supplying the populations of large cities is effected at an elevated cost, given that this cost does not include solely the price of generating the electric power itself, i.e., production, storage, labor, maintenance of installations, distribution, etc., but, in addition, bears the associated costs of damage to the environment due to the production of residual pollutants, and the consequent damage to the health of humans, and to the flora and fauna.
In a recent work we reported that chemically deposited intrinsic CdS thin films can be converted ... more In a recent work we reported that chemically deposited intrinsic CdS thin films can be converted into n-type with an electrical conductivity of 0268-1242/11/7/021/img1 by solid state diffusion of indium at temperatures of 0268-1242/11/7/021/img2 from a thin film of indium deposited by thermal evaporation on the CdS surface. In the present study, we report on the enhancement of grain size
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