Physics of intraband quantum dot optoelectronic devices

摘要: In last two decades, semiconductor nanostructures, such as quantum wells, wires and dots, have been recognised sources detectors of radiation in the mid- far-infrared region spectrum. Much a success has obtained with well based intraband devices, cascade lasers infrared photodetectors. However due to longer carrier lifetimes it is expected that optoelectronic devices on transitions self-assembled dots would superior performance their counterparts. order fully exploit this prospect, appropriate theoretical models describing electronic, optical transport properties active these need be developed, which was subject thesis. It shown how symmetry dot shape can exploited efficiently calculate energy levels within framework multiband envelope function method. The implementation method plane wave representation Hamiltonian eigenvalue problem results its application square pyramidal InAs/GaAs hexagonal III-nitride were given. A semiclassical model dynamics then developed applied design an optically pumped long wavelength mid-infrared laser intersublevel dots. Two orders magnitude lower pumping flux predicted than similar devices. Next, simulations absorption spectrum existing photodetector structures performed. A special emphasis put into dots-in-a-well explanation effect width detection wavelength. A theory photodetectors starting from wavefunctions by solving Hamiltonian, yielding output device characteristics dark current responsivity, developed. comparison experimental data available literature made, good agreement. Finally, electron through arrays closely stacked where coherent polaronic effects become important, therefore requiring treatment formalism nonequilibrium Green's functions, rather approach, presented. structure promising act terahertz