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

Alberto, H. V.; Vilão, R. C.; Ribeiro, E. F. M.; Gil, J. M.; Curado, M. A.; Teixeira, J. P.; Fernandes, P. A.; Cunha, J. M. V.; Salomé, P. M. P.

The slow muon technique was used to study the p-n junction of chalcopyrite solar cells. A defect layer near the interface was identi ed and the passivation of the defects by bu er 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 ext...


Sapphire α−Al2O3 puzzle: Joint μSR and density functional theory study

Vilão, R. C.; Marinopoulos, A. G.; Alberto, H. V.; Gil, J. M.; Lord, J. S.; Weidinger, A.

Sapphire (α-Al2O3) has been investigated by the muon spin rotation (µSR) method in several experiments in the past. The main µSR component is a diamagnetic-like signal with a fast relaxation. Because of this diamagnetic-like behavior, the signal was assigned to either positively charged muonium (Mu+) or negatively charged muonium (Mu−), but neither of the two assignments was satisfactory (the so-called “sapphir...


Hydrogen states in mixed-cation CuIn(1−x)GaxSe2 chalcopyrite alloys: a combined...

Marinopoulos, A. G.; Vilão, R. C.; Alberto, H. V.; Ribeiro, E. F. M.; Gil, J. M.; Mengyan, P. W.; Goeks, M. R.; Kauk-Kuusik, M.; Lord, J. S.

First-principles calculations were performed jointly with muon-spin (µSR) spectroscopy experiments in order to examine the electrical activity of hydrogen in mixed-cation chalcopyrite Cu(In1−x,Gax)Se2 (CIGS) alloys and other related compounds commonly used as absorbers in solar-cell technology. The study targeted the range of Ga concentrations most relevant in typical solar cells. By means of a hybridfunctional...


Reply to “Comment on ‘Role of the transition state in muon implantation’ and ‘T...

Vilão, R. C.; Alberto, H. V.; Vieira, R. B. L.; Gil, J. M.; Weidinger, A.


Front passivation of Cu(In,Ga)Se2 solar cells using Al2O3: culprits and benefits

Curado, M. A.; Teixeira, J. P.; Monteiro, M.; Ribeiro, E. F. M.; Vilão, R.C.; Alberto, H. V.; Cunha, J. M. V.; Lopes, T.S.; Oliveira, K.

In recent years, the strategies used to break the Cu(In,Ga)Se2 (CIGS) world record of light to power conversion efficiency, were based on improvements of the absorber optoelectronic and crystalline properties, mainly using complex post-deposition treatments. To reach even higher efficiency values, advances in the solar cell architecture are needed focusing in the CIGS interfaces. In this study, we evaluate the ...


Muon implantation experiments in films: obtaining depth-resolved information

Simões, A. F. A.; Alberto, H. V.; Vilão, R. C.; Gil, J. M.; Cunha, J. M. V.; Curado, M. A.; Salomé, P. M. P.; Prokscha, T.; Suter, A.; Salman, Z.

Implanted positive muons with low energies (in the range 1-30 keV) are extremely useful local probes in the study of thin films and multi-layer structures. The average muon stopping depth, typically in the order of tens of nanometers, is a function of the muon implantation energy and of the density of the material, but the stopping range extends over a broad region, which is also in the order of tens of nanomet...


Thermal spike in muon implantation

Vilão, R. C.; Alberto, H. V.; Gil, J. M.; Weidinger, A.


Slow-muon study of quaternary solar-cell materials: Single layers and p-n junct...

Alberto, H. V.; Vilão, R. C.; Vieira, R. B. L.; Gil, J. M.; Weidinger, A.; Sousa, M. G.; Teixeira, J. P.; Cunha, A. F.; Leitão, J. P.; Salomé, P. M. P.


Slow-muon study of quaternary solar-cell materials: single layers and p−n junct...

Alberto, H. V.; Vilão, R. C.; Vieira, R. B. L.; Gil, J. M.; Weidinger, A.; Sousa, M. G.; Teixeira, J. P.; Cunha, A. F. da; Leitão, J. P.

Thin films and p-n junctions for solar cells based on the absorber materials Cu(In,Ga)Se2 and Cu2ZnSnS4 were investigated as a function of depth using implanted low energy muons. The most significant result is a clear decrease of the formation probability of the Mu+ state at the heterojunction interface as well as at the surface of the Cu(In,Ga)Se2 film. This reduction is attributed to a reduced bonding reactio...


The role of the transition state in muon implantation

Vilão, R. C.; Vieira, R. B. L.; Alberto, H. V.; Gil, J. M.; Weidinger, A.

In muon-spin-rotation experiments, positive muons are implanted in the material and come to rest in the unrelaxed host lattice. The formation of the final configuration requires a lattice relaxation which does not occur instantly. The present paper is concerned with the transition from the initial stopping state to the final muon configuration. We identify the often observed fast relaxing signal in muon experim...


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