U
U. Jahn
Researcher at Tokyo Institute of Technology
Publications - 82
Citations - 1940
U. Jahn is an academic researcher from Tokyo Institute of Technology. The author has contributed to research in topics: Cathodoluminescence & Molecular beam epitaxy. The author has an hindex of 20, co-authored 82 publications receiving 1855 citations.
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Journal ArticleDOI
Luminescence properties and defects in GaN nanocolumns grown by molecular beam epitaxy
Enrique Calleja,Miguel Sanchez-Garcia,F. J. Sanchez,Fernando Calle,Fernando B. Naranjo,E. Muñoz,U. Jahn,K. H. Ploog +7 more
TL;DR: Wurtzite GaN nanocolumns are reproducibly grown by plasma-assisted molecular beam epitaxy on Si(111) and c-sapphire substrates.
Journal ArticleDOI
Growth, morphology, and structural properties of group-III-nitride nanocolumns and nanodisks
E. Calleja,J. Ristic,Sergio Fernández-Garrido,Laurent Cerutti,Laurent Cerutti,Miguel Sanchez-Garcia,Javier Grandal,Achim Trampert,U. Jahn,G. Sánchez,Amadeu Griol,B. Sánchez +11 more
TL;DR: In this paper, the growth conditions to achieve group-III-nitride nanocolumns by plasma-assisted molecular beam epitaxy are studied, and the evolution of the morphology of (Ga,Al)N and (In,Ga)N nanocumns with high N-rich conditions are determined.
Journal ArticleDOI
Identification of optical transitions in cubic and hexagonal GaN by spatially resolved cathodoluminescence.
TL;DR: Detailed temperature-and intensity-dependent CL measurements on cubic GaN crystals enable us to clearly identify the exciton and donor-acceptor pair transition energy and determine the donor-band and acceptor-band transition energy for this phase.
Journal ArticleDOI
Characterization of GaN quantum discs embedded in Al x Ga 1 − x N nanocolumns grown by molecular beam epitaxy
Jelena Ristic,E. Calleja,Miguel Sanchez-Garcia,JM José Maria Ulloa,J. Sánchez-Páramo,J. M. Calleja,U. Jahn,Achim Trampert,K. H. Ploog +8 more
TL;DR: In this article, GaN quantum discs embedded in AlGaN nanocolumns with outstanding crystal quality and very high luminescence efficiency were grown on Si(111) substrates by plasma-assisted molecular beam epitaxy under highly N-rich conditions.
Journal ArticleDOI
Understanding the selective area growth of GaN nanocolumns by MBE using Ti nanomasks
A. Bengoechea-Encabo,F. Barbagini,Sergio Fernández-Garrido,Javier Grandal,J. Ristic,Miguel Sanchez-Garcia,Enrique Calleja,U. Jahn,Esperanza Luna,Achim Trampert +9 more
TL;DR: In this paper, the influence of the substrate temperature, III/V flux ratio, and mask geometry on the selective area growth of GaN nanocolumns is investigated, and the mask design is found to be crucial to achieve selective growth within the nanoholes.