Accueil >
Production scientifique
Composants et capteurs
(24) Production(s) de l'année 2018
|
|
Properties of MAPbI3 perovskite layers grown with HCl additions 
Auteur(s): Moret M., Tiberj A., Desrat W., Briot O.
(Article) Publié:
Superlattices And Microstructures, vol. 120 p.136 (2018)
Ref HAL: hal-01802768_v1
DOI: 10.1016/j.spmi.2018.05.033
WoS: 000445713700016
Exporter : BibTex | endNote
Résumé: Lead halide perovskites, used to produce photovoltaic devices, have been thesubject of a huge research effort these last years. This is due to the spectac-ular improvement of the conversion effciency results within a short amount oftime. However, some issues have been identified, which include stability, leaduse and cost of some precursors. It has recently been shown that low purity, lowcost PbI2 could be succesfully used in the synthesis of the MAPbI3 perovskite,provided that HCl is added during the synthesis to prevent solubility problems.Thus, it is of high interest to provide information pertaining to the materialquality, in relation with the HCl additions performed during synthesis. In thiswork, we have grown three sets of samples with different HCl to (PbI 2 + MAI)molar ratios (R HCl ), where PbI2 and methylamine iodide (MAI) are the precur-sors of the perovskite. We used RHCl = 0 (no HCl), 0.5 and 1.2 . We performedx-ray diffraction, transmittance and 77K photoluminescence experiments in or-der to assess the material structural and optoelectronic properties and foundthat an optimum HCl concentration must be used. HCl introduction clearlyhas a beneficial effect both on domain sizes and photoluminescence intensityat RHCl = 0.5, but lead to subsequent degradation of the perovskite quality athigher RHCl .
|
|
|
|
Temperature-Induced Topological Phase Transition in HgTe Quantum Wells
Auteur(s): Kadykov A., Krishtopenko S., Jouault B., Desrat W., Knap W., Ruffenach S., Consejo C., Torres Jeremie, Morozov S. V., Mikhailov N. N., Dvoretskii S. A., Teppe F.
(Article) Publié:
Physical Review Letters, vol. 120 p.086401 (2018)
Texte intégral en Openaccess : 
Ref HAL: hal-01740166_v1
Ref Arxiv: 1710.06666
DOI: 10.1103/PhysRevLett.120.086401
WoS: WOS:000425738500007
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
29 Citations
Résumé: We report a direct observation of temperature-induced topological phase transition between trivial and topological insulator in HgTe quantum well. By using a gated Hall bar device, we measure and represent Landau levels in fan charts at different temperatures and we follow the temperature evolution of a peculiar pair of "zero-mode" Landau levels, which split from the edge of electron-like and hole-like subbands. Their crossing at critical magnetic field Bc is a characteristic of inverted band structure in the quantum well. By measuring the temperature dependence of Bc, we directly extract the critical temperature Tc at which the bulk band-gap vanishes and the topological phase transition occurs. Above this critical temperature, the opening of a trivial gap is clearly observed.
Commentaires: 5 pages + Supplemental Materials
|
|
|
|
Optimization of the properties of the molybdenum back contact deposited by radiofrequency sputtering for Cu( In 1 − x Ga x ) Se 2 solar cells
Auteur(s): Briot O., Moret M., Barbier Camille, Tiberj A., Peyre H., Sagna A., Contreras S.
(Article) Publié:
Solar Energy Materials And Solar Cells, vol. 174 p.418 - 422 (2018)
|
