Sökning: "carrier multiplication"

Hittade 5 avhandlingar innehållade orden carrier multiplication.

1. 1. Spatiotemporal carrier dynamics in graphene

   Författare :Roland Jago; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; spatiotemporal dynamics; density matrix formalism; graphene; relaxation dynamics; carrier multiplication; Bloch equations; photoconduction effect; bolometric effect;

   Sammanfattning : Graphene as an atomically thin material exhibits remarkable optical and electronic properties that suggest its technological application in novel optoelectronic devices, such as graphene-based photodetectors and lasers. To understand the properties of such devices on a microscopic level, we study the interplay of optical excitation, carrier-carrier, carrier-phonon, and carrierphoton scattering as well as diffusion processes. LÄS MER

3. 2. Electron dynamics in graphene in the presence of an electrical field

   Författare :Roland Jago; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Bloch equations; density matrix formalism; graphene; relaxation dynamics; photoconduction effect; carrier multiplication;

   Sammanfattning : Graphene as atomically thin two-dimensional material exhibits remarkableoptical and electronic properties that suggest its technological applicationin novel optoelectronic devices, such as graphene-based lasers and photodetectors.The linear electronic bandstructure and the vanishing band gap atthe Dirac point open up new relaxation channels, such as Auger scattering. LÄS MER

4. 3. Generation, Modulation, and Detection of Signals in Microwave Photonic Systems

   Författare :Andreas Wiberg; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Microwave photonics; radio over fiber; mm-wave generation; PSK; QAM; subcarrier modulation; photonic frequency multiplication; spurious free dynamic range third-order intercept point; millimeter-wave photonics; uni-travelling-carrier photodiode; millimeter-wave communication system;

   Sammanfattning : This thesis deals with the use of photonic technology in microwave and millimeter-wave applications. The two major parts of this work have been techniques for transmission and signal generation. LÄS MER

5. 4. Design of Wireless Communication Systems -- Issues on Synchronization, Channel Estimation and Multi-Carrier Systems

   Författare :Fredrik Tufvesson; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; pre-compensation; pilot pattern; Elektronik; orthogonal frequency division multiplex; Wireless; synchronization; detection; preambles; channel estimation; Electronics; superimposed pilot sequences; sub-channel bandwidth; precoding;

   Sammanfattning : This thesis deals with certain aspects in the design of wireless communications systems. It is focused on problems related to the mobile or wireless channel: synchronization, channel estimation and design of wireless orthogonal frequency division multiplex (OFDM) systems. LÄS MER

7. 5. Millimeter-Wave Photonics: Signal Sources and Transmission Links

   Författare :Andreas Wiberg; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; microwave photonics; mm-wave generation; radio over fiber; photonic frequency multiplication; millimeter-wave photonics; millimeter-waves; millimeter-wave communication system;

   Sammanfattning : With the use of higher and higher frequencies in a number of current and future wireless millimeter-wave applications it is beneficial to use photonics for several reasons. The use of optical fibers is an advantageous way to transport millimeter-waves in terms of loss, mechanical flexibility, weight, and insensitivity to electromagnetic interference. LÄS MER