Grafen ve karbon nanotüp ile nanoölçekli kablosuz optik haberleşme alıcıları

Graphene and carbon nanotube are two popular building blocks of nanotechnology with significant electronic, optical, mechanical and thermal properties and diverse growing application areas in physical, chemical, biological and technological sciences. Graphene as a tiny two-dimensional atomic layer carbon sheet and its rolled version into nanometer scale diameter nanotubes have been used in field effect transistor structures with significant electronic and optoelectronic properties. Metal-graphene-metal (MGM) photodetectors with single or multi-layer graphene sheets are promising for future nanoscale optical communication architectures because of wide range absorption from far infrared to visible spectrum, fast carrier velocity and advanced production techniques due to planar geometry. Similarly, carbon nanotube field-effect transistors (CNTFETs) show significant photodetection performances due to wide spectral region, tunable band-gap and fast carrier velocity. Both of the structures with nanoscale dimensions and efficient optoelectronic properties open the possibility to be used in next generation optical wireless communication (OWC) networking architectures. In this thesis, the communication theoretical modeling and analysis of nanoscale optical wireless receivers based on single layer graphene (SLG) and single walled nanotubes (SWNTs) are established.The performance limitations of photodetectors due to their resistive and capacitive elements, and carrier velocity are analyzed. The fundamental communication theoretical performance metrics, i.e., signal-to-noise ratio (SNR), bit-error rate (BER) and data rate, are theoretically modeled and numerically simulated. It is shown that tens of Gb/s and hundreds of Mb/s data rates for SLG and SWNT, respectively, can be achieved with practical power levels where intrinsic THz data range communication capability is explored. Thermal and shot noise limited regimes of the photodetectors are explored with respect to varying transmit power levels. Furthermore, diversity combining methods for multi-receiver graphene detectors are introduced which increase the efficiency of the detectors. Moreover, broadcast information network for nanotube networks are introduced in a transmit power optimization framework. The communication theoretical modeling and performance analysis of graphene and carbon nanotube optical receivers lay the foundations for next generation nanoscale wireless optical communication architectures.