Johan Bergsten
Chalmers University of Technology
31 Papers
229 Citations
Johan Bergsten is an academic researcher from Chalmers University of Technology. The author has contributed to research in topics: Ohmic contact & High-electron-mobility transistor. The author has an hindex of 13, co-authored 28 publications.
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Papers
•Posted Content
Enhanced Tunnel Spin Injection into Graphene using Chemical Vapor Deposited Hexagonal Boron Nitride
TL;DR: In this article, a spin-polarized electron tunneling through 2D hexagonal boron nitride (h-BN) contacts was demonstrated for spin transport and precession over micrometer-scale distances with spin lifetime up to 46 nanosecond.
120
Dispersive Effects in Microwave AlGaN/AlN/GaN HEMTs With Carbon-Doped Buffer
Sebastian Gustafsson,Jr-Tai Chen,Johan Bergsten,Urban Forsberg,Mattias Thorsell,Erik Janzén,Niklas Rorsman +6 more
TL;DR: In this paper, three epitaxial structures have been fabricated on 4H-SiC using hot-wall metal-organic chemical vapor deposition with residual carbon doping, and the leakage currents in OFF-state at 10 V drain voltage were in the same order of magnitude ( $10^{-4}$ A/mm) for the high-doped and steppeddoped buffer.
78
Spin transport and precession in graphene measured by nonlocal and three-terminal methods
TL;DR: In this paper, the spin transport and precession in graphene were investigated by using the Hanle effect in nonlocal and three-terminal measurement geometries, and identical spin lifetimes, spin diffusion lengths, and spin polarizations were observed in graphene devices for both techniques over a wide range of temperatures.
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Suppression of Dispersive Effects in AlGaN/GaN High-Electron-Mobility Transistors Using Bilayer SiN x Grown by Low Pressure Chemical Vapor Deposition
Tongde Huang,Anna Malmros,Johan Bergsten,Sebastian Gustafsson,Olle Axelsson,Mattias Thorsell,Niklas Rorsman +6 more
TL;DR: In this article, a bilayer SiN x passivation scheme using low pressure chemical vapor deposition (LPCVD) was developed, which effectively suppresses the dispersive effects in AlGaN/GaN high-electron-mobility transistors (HEMTs) for microwave power operation.
30
Low resistive Au-free, Ta-based, recessed ohmic contacts to InAlN/AlN/GaN heterostructures
Johan Bergsten,Anna Malmros,M. Tordjman,Piero Gamarra,Cedric Lacam,M. A. di Forte-Poisson,Niklas Rorsman +6 more
TL;DR: In this paper, the formation of recess etched Au-free ohmic contacts to an InAlN/Al N/GaN heterostructure was investigated, where a Ta/Al/Ta metal stack was used to produce contacts with contact resistance (R-c) as low as 0.14 Omega mm.
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