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Tham khảo sách 'semiconductor technologies_2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 11 Electron transport effect on optical response of quantum-cascade structures Mykhailo Klymenko and Oleksiy Shulika Kharkov National University of Radio Electronics Ukraine Igor Sukhoivanov University of Guanajuato Mexico 1. Introduction The quantum-cascade laser is an unique source of the THz laser radiation operated in continuous-wave and pulse regimes Gmachl et al 2001 . History of these lasers counts more than ten years. However many aspects of the carrier transport and interaction with light field are still unclear. Very important question concerning physics of the quantum-cascade structures QCS is the following which kind of transport coherent or incoherent is prevailed in QCS There were many discussions about the problem and several attempts to estimate kind of transport were successful especially Iotti et al 2001 Weber et al 2009 . The answer on this question depends on conditions of QCS operation. For example the coherent electron transport is of interest in the non-equilibrium regime at femtosecond and picosecond time intervals. The incoherent transport is prevalent at the high excitation level in the stationary quasi-equilibrium regime. In both cases the electron transport influence on optical properties of the device. In this connection the development of the theory for coherent and incoherent electron transport regimes included many-body effects and light-matter interactions in QCS is of actual interest. In this chapter we provide modeling of optical and transport properties of QCS uncovering influence of the electron transport on optical characteristics. Lasing light absorption and spontaneous emission in QCS are accompanied and affected by many complicated transport processes such as electron diffusion drift tunneling recombination generation capture and escape mediated by electron-electron electron-phonon and electron-photon scattering events Piprek 2005 . Most of these effects can be treated within the quasi-equilibrium approximation. However the
