Optimizing ballistic nanodevices towards THz applications
(2007)
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Details
- Authors
- Supervisors
- Huynen, Isabelle
- Abstract
- Because of the increasing amount of information to be transmitted, developing digital/analog electronic devices for data processing at ultra-high bit rates and/or on high frequency carriers is a key issue. There is for example a growing interest for ultra-high bit rates transmission systems (80 Gbits/s and 160 Gbits/s) on optical carriers. In such systems, basic electronic devices operating up to THz frequencies are mandatory for implementing the following functions: amplifiers, samplers, MUX/DEMUX devices, AD/DA converters, and millimetre/infrared wave detectors. Another example is the direct modulation/demodulation of the carrier in telecommunication applications (software radio). If terahertz devices are available to realize ultra high speed DAC/ADC, the transceiver architecture can be highly simplified by replacing all high-frequency analog front-end with all-digital system, while presenting better digital robustness, frequency agility, lower power consumption, complex modulation schemes (spread spectrum) and simultaneous operation on many bands. For all these applications, nanometre-scale ballistic devices would allow extending the cut-off frequency FC of the devices in the THz range and hence are of prime interest. Ballistic devices are devices with characteristic dimensions (Lc) smaller than electron mean-free-path (le). In such devices the electrons move ballisticaly through the device i.e without scattering and loosing the energy. The advantage of ballistic devices is a very short electron transit time ô in the order of tens of femtoseconds (ô=Lc/vF where vF is Fermi velocity). The limiting frequency of operation FC for such short transit times lies in the THz frequency range. This thesis is aiming at investigating the possibility of using this tremendous advantage over classical "diffusive" devices for high bit-rate data processing. The work intended to design, fabricate and characterize ballistic devices up to room temperature and up to millimeter wave frequencies in view of developing digital/analog electronic devices for terahertz data processing.
- Affiliations
Citations
Bednarz, L. (2007). Optimizing ballistic nanodevices towards THz applications. https://hdl.handle.net/2078.5/97587