Photoluminescence of Nd-doped SnO2 thin films

Structural, optical, and electrical properties of Nd-doped SnOx thin films are reported. The atomic structure was characterized by x-ray diffraction and infrared absorption spectrometry. Investigation of the photoluminescence properties revealed Nd-related bands at 920 and 1100 nm for samples annealed at 700 degrees C, which present the tetragonal structure of the SnO2 rutile phase. Nd3+ ions can be indirectly excited and no concentration quenching was observed up to 3 at. %. It is concluded that Nd3+ ions are efficient optically active dopants in addition to be responsible of the observed electric conductivity improvement. These materials are then interesting for solar cell applications

Optical and structural properties of Nd doped SnO2 powder fabricated by the sol-gel method

We report on the structural and optical properties of undoped and neodymium doped SnO2 powders (0, 1, 3, and 5 at% of Nd) synthesized by the sol-gel method. SEM and TEM microscopy techniques reveal a nanometric scale of the powders. We show that the tetragonal rutile phase is achieved after annealing at 700 degrees C. The crystallite size of the doped SnO2 is found to decrease gradually with the increase of Nd content without changing the SnO2 structure. A strong decrease in the intensity of the Raman peaks is noted for doped powders, which can be attributed to the location of Nd3+ ions at the Sn sites indicating Nd incorporation into the host matrix. For the first time the optical properties were studied by UV-VisNIR spectroscopy and revealed Nd related absorption bands in the SnO2 matrix. The investigation of the photoluminescence properties shows broad emission centred around 550-650 nm originating from defects present in the SnO2 host matrix. Under 325 nm laser excitation, a strong photoluminescence of trivalent Nd is observed in the infrared region and shows Nd related emission peaks at 885, 1065, and 1336 nm. Such a strong PL signal under laser excitation indicates that Nd3+ is optically active. The excitation dependent PL (PLE) recorded in the 450-700 nm range confirms the presence of active Nd3+ successfully inserted into the SnO2 host matrix

Evaluation of the effective quantum efficiency of photon conversion layers placed on solar cells

Équipe 104 : NanomatériauxInternational audiencePhoton conversion layers are a possible way of improving the efficiency of existing solar cells, even above the Shockley-Queisser limit. The related concepts are often called downshifting, downconversion, and upconversion. Despite the variety of photon conversion systems proposed in the literature, understanding their real impact is often difficult due to joint effects. Here, a new methodology is provided to analyse the efficiency of such conversion layers and to be able to compare the different systems proposed

Deposition of thin layers of zinc oxide and characterization of resonators

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Preparation of ZnO thin films by reactive e-beam evaporation technique

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Structural and optical properties of ZnO fabricated by reactive e-beam and rf magnetron sputtering techniques

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Sputtering R.F magnetron applied to the deposition of ZnO thin films for sensors and biosensors fabrication

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Feasability of a new sensor for water activity determination

International audienceIn this paper, we propose a new way for the determination of aw in fresh and salt meat. The principle is founded on the analysis of a small air volume inside the product. First we describe the fundamental definition of water activity, the state-of-the-art of commercial aw meters, the effects of aw on microbiology in food. In the second step, after a description of the sensor, the principle and the procedure of measurement are explained. The measurements of aw are realized in meat at different stages of drying. Reproducibility and the temperature effect are particularly analyzed

Sputtering R.F magnetron applied to the deposition of ZnO thin films for sensors and biosensors fabrication

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laboration and characterization of piezoelectric zinc oxide thin films for application in Bulk Acoustic Wave resonator

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