Recursos em areias e cascalhos ao largo da ilha de S. Miguel, Açores

A campanha de geofísica SAMI-1 realizada ao largo da Ilha de S. Miguel (Açores) permitiu a aquisição de perfis sísmicos de alta resolução (Boomer) e de batimetria detalhada. Estes dados possibilitaram a definição das áreas mais promissoras em inertes (areias e cascalhos) na plataforma insular de S. Miguel. Deverão ser efectuados estudos de pormenor de forma a caracterizar estas áreas, para servirem de apoio à elaboração de um plano de gestão da extracção de inertes em redor das ilhas

Recursos em areias e cascalhos ao largo da Ilha do Pico, Açores

A campanha FAPI-2 realizada ao largo da ilha do Pico (Açores) permitiu a aquisição de perfis sísmicos de alta resolução (Chirp Sonar e Boomer) e de batimetria detalhada. Estes dados possibilitaram a definição das áreas mais promissoras em inertes (areias e cascalhos) na plataforma continental do Pico. Os resultados mostram que as áreas mais promissoras, são as que conjugam uma espessura elevada de sedimentos e um baixo declive de fundo

Low energy muon study of the p-n interface in chalcopyrite solar cells

The slow muon technique was used to study the p-n junction of chalcopyrite solar cells. A defect layer near the interface was identified and the passivation of the defects by buffer layers was studied. Several cover layers on top of the chalcopyrite Cu(In,Ga)Se2 (CIGS) semiconductor absorber were investigated in this work, namely CdS, ZnSnO, Al2O3 and SiO2. Quantitative results were obtained: The defect layer extends about 50 nm into the CIGS absorber, the relevant disturbance is strain in the lattice, and CdS provides the best passivation, oxides have a minor effect. In the present contribution, specific aspects of the low-energy muon technique in connection with this research are discussed

Characterization of the Interfacial Defect Layer in Chalcopyrite Solar Cells by Depth‐Resolved Muon Spin Spectroscopy

As devices become smaller and more complex, the interfaces between adjacent materials become increasingly important and are often critical to device performance. An important research goal is to improve the interface between the absorber and the window layer by inserting buffer layers to adjust the transition. Depth-resolved studies are key for a fundamental understanding of the interface. In the present experiment, the interface between the chalcopyrite Cu(In,Ga)Se2 absorber and various buffer layers are investigated using low-energy muon spin rotation (μSR) spectroscopy. Depth resolution in the nm range is achieved by implanting the muons with different energies so that they stop at different depths in the sample. Near the interface, a region about 50 nm wide is detected where the lattice is more distorted than further inside the absorber. The distortion is attributed to the long-range strain field caused by defects. These measurements allow a quantification of the corresponding passivation effect of the buffer layer. Bath-deposited cadmium sulfide provides the best defect passivation in the near interface region, in contrast to the dry-deposited oxides, which have a much smaller effect. The experiment demonstrates the great potential of low energy μSR spectroscopy for microscopic interfacial studies of multilayer systems.This work is based on experiments performed at the Swiss Muon Source (SμS), Paul Scherrer Institute, Villigen, Switzerland. A.W. thanks Prof. Klaus Lips for the invitation to the Helmholtz-Zentrum Berlin für Materialien und Energie. This work was supported with funds from FEDER (Programa Operacional Factores de Competitividade COMPETE) and by national funds from FCT - Fundação para a Ciância e Tecnologia, I. P. (Portugal) under projects PTDC/FIS-MAC/29696/2017, PD/BD/142780/2018, UID/04564/2020, UIDB/04730/2020, UIDP/04730/2020, UIDB/50025/2020, and UIDP/50025/2020.info:eu-repo/semantics/publishedVersio

Cu(In,Ga)Se2 based ultrathin solar cells the pathway from lab rigid to large scale flexible technology

The incorporation of interface passivation structures in ultrathin Cu(In,Ga)Se2 based solar cells is shown. The fabrication used an industry scalable lithography technique—nanoimprint lithography (NIL)—for a 15 × 15 cm2 dielectric layer patterning. Devices with a NIL nanopatterned dielectric layer are benchmarked against electron-beam lithography (EBL) patterning, using rigid substrates. The NIL patterned device shows similar performance to the EBL patterned device.The impact of the lithographic processes in the rigid solar cells’ performance were evaluated via X-ray Photoelectron Spectroscopy and through a Solar Cell Capacitance Simulator. The device on stainless-steel showed a slightly lower performance than the rigid approach, due to additional challenges of processing steel substrates, even though scanning transmission electron microscopy did not show clear evidence of impurity diffusion. Notwithstanding, time-resolved photoluminescence results strongly suggested elemental diffusion from the flexible substrate. Nevertheless, bending tests on the stainless-steel device demonstrated the mechanical stability of the CIGS-based device