447 research outputs found
Meuris Georges — Les aptitudes au niveau de l'enseignement secondaire
No full textC. P. Meuris Georges — Les aptitudes au niveau de l'enseignement secondaire. In: Population, 21ᵉ année, n°6, 1966. pp. 1232-1233
Sensitive light scattering as a semiquantitative method for studying photoresist stripping
No full textCrystallization properties of Cu<sub>2</sub>ZnGeSe<sub>4</sub>
No full text© 2018 We have studied the crystallization reaction of polycrystalline Cu2ZnGeSe4 solar cell absorbers fabricated by H2Se selenization of sequentially deposited metal layer stacks. We have executed a stop experiment, stopping the crystallization reaction at different times during the process, then analyzing the subsequent X-ray diffraction patterns. We have found that mainly Cu3Ge and ZnSe phases form very rapidly at temperatures below 350 °C. Depending on the order of the sequentially deposited metal layer stack, the formation reaction proceeds at different speeds. Putting the Ge layer in the bottom and the Cu layer on top leads to a very fast nucleation reaction of Cu2ZnGeSe4, leading to small grains that have obtained their final size already after 3 min of selenization at 460 °C. The inverse stack with Ge on top and Cu in the bottom delays the nucleation of Cu2ZnGeSe4, leading to a somewhat slower formation reaction and larger Cu2ZnGeSe4 grains, which obtain their final grain size only after 15 min of selenization at 460 °C.sponsorship: This research is partially funded by the Flemish government, Department Economy, Science and Innovation. This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 640868. B. Vermang acknowledges the financial support of the Flemish Research Foundation FWO (mandate 12O4215N). (Flemish government, Department Economy, Science and Innovation, European Union's Horizon 2020 research and innovation program|640868, Flemish Research Foundation FWO|12O4215N, H2020 Societal Challenges Programme|640868)status: Publishe
Characterization of defects in 9.7 efficient Cu2ZnSnSe4 CdS ZnO solar cells
No full textWe have fabricated Cu2ZnSnSe4-CdS-ZnO solar cells with a total area efficiency of 9.7%. The absorber layer was fabricated by selenization of sputtered Cu10Sn90, Zn, and Cu multilayers. A large ideality factor of the order of 3 is observed in both illuminated and dark IV-curves, which seems to point in the direction of complex recombination mechanisms such as recombination through fluctuating potentials in the conduction and valence bands of the solar cell structure. A potential barrier of about 135 meV in the device seems to be responsible for an exponential increase of the series resistance at low temperatures, but at room temperature, the effect of this barrier remains relatively small. The free carrier density in the absorber is of the order of 10(15) cm(-3) and does not vary much as the temperature is decreased. (C) 2013 AIP Publishing LLC
Development of co-evaporated In2S3 buffer layer for Cu2ZnSnSe4 thin film solar cells
No full textIn this work, we focus on the replacement of the commonly used but toxic Cd-based buffer layer by In2S3 thin films deposited by co-evaporation for application in Cu2ZnSnSe4 (CZTSe) solar cells. The impact of the deposition conditions of the buffer layer on the electrical behavior of CZTSe/In2S3 devices is first investigated. The best solar cell efficiencies were obtained for relatively thick In2S3 buffer layers (similar to 100 nm) deposited at low temperature (<100 degrees C). It is also observed that low [Cu]/([Zn]+[Sn]) ratio (CZT similar to 0.75) in the kesterite absorber leads to high efficiency for In-based buffered CZTSe solar cells, while the effect of the CZT ratio on CZTSe/CdS solar cell performances is not so clear. A conversion efficiency of 5.7 % on CZTSe/In2S3 thin film solar cell is achieved
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