Jouni Ahopelto

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We study the relaxation of coherent acoustic phonon modes with frequencies up to 500 GHz in ultrathin free-standing silicon membranes. Using an ultrafast pump-probe technique of asynchronous optical sampling, we observe that the decay time of the first-order dilatational mode decreases significantly from ~4.7 ns to 5 ps with decreasing membrane thickness(More)
Hydrogenated amorphous silicon (a-Si:H) has been already considered for the objective of passive optical elements, like waveguides and ring resonators, within photonic integrated circuits at λ = 1.55 μm. However the study of its electro-optical properties is still at an early stage, therefore this semiconductor in practice is not considered for light(More)
Low temperature mobility measurements of silicon-on-insulator ͑SOI͒ metal-oxide-field-effect-transistors are reported. The batch of devices fabricated in this work includes both ultrathin and thick devices for which the SOI film thicknesses are in the ranges of 10–15 nm and 56 – 61 nm, respectively. The 4.2 K peak mobility of the thick devices is 1.9 m 2 /V(More)
Understanding and controlling vibrations in condensed matter is emerging as an essential necessity both at fundamental level and for the development of a broad variety of technological applications. Intelligent design of the band structure and transport properties of phonons at the nanoscale and of their interactions with electrons and photons impact the(More)
The interaction between the design and the technology research communities working in nanoelectronics, and especially in the Beyond CMOS area, is characterised by a diversity of terminologies, modi operandi and the absence of a consensus on main priorities. We present the findings of the EU project NANO-TEC to date, in the quest to bring together these(More)
NanoICT position papers aim to be a valid source of guidance for the semiconductor industry (roadmapping), providing the latest developments in the fi eld of emerging nanoelectronic devices that appears promising for future take up by the industry. This E-Nano newsletter issue contains two new position papers from the EU funded nanoICT Coordination Action(More)
Heat dissipation in nanometer-scale ridges The raise up of UHV atomic scale interconnection machines This edition contains two articles providing new insights in a relevant fi eld for future nano-electronics applications, i.e. molecular computing at the atomic scale. Since 1974, Molecular electronics had been always associated to the possible future of(More)
  • J Ahopelto, M Co-Ordinator, K Prunnila, M Henttinen, Markkanen, F Gamiz +4 others
  • 2004
This one-year Assessment Project focused on realisation and demonstration of velocity modulation operation in silicon-based devices. Transistors operating in velocity modulation mode (VMT) have a promise for very high operation speed. The project concentrated on verifying the essential requirements for velocity modulation: a) to switch the electron gas(More)
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