Nizami Vagidov

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We report a 50% increase in the power conversion efficiency of InAs/GaAs quantum dot solar cells due to n-doping of the interdot space. The n-doped device was compared with GaAs reference cell, undoped, and p-doped devices. We found that the quantum dots with built-in charge (Q-BIC) enhance electron intersubband quantum dot transitions, suppress fast(More)
Potential barriers around quantum dots (QDs) play a key role in kinetics of photoelectrons. These barriers are always created, when electrons from dopants outside QDs fill the dots. Potential barriers suppress the capture processes of photoelectrons and increase the photoresponse. To directly investigate the effect of potential barriers on photoelectron(More)
Band-structure effects on channel carrier density in the ultrathin-body end of the ITRS roadmap silicon (100) n-type metal oxide semiconductor field effect transistors (MOSFETs) are assessed here using a semi-empirical nearest-neighbor sp 3 d 5 s à tight-binding model with spin-orbit interaction. The calculations focus on the body thickness range between 10(More)
A dispersion relation for an electron in a two-layer ~and also multilayer! quantum well ~QW! is formed as a result of a certain combination of initial dispersion relations for each of the forming layers. Such a combination can be used to engineer new dispersion relations with desirable properties. The same relates to a two-dimensional electron gas ~2DEG!(More)
Results of our many-particle Monte-Carlo modeling of kinetics and transport of electrons in InAs/GaAs quantum-dot infrared photodetectors are reviewed. We studied the dependence of the electron capture time on the electric field at different heights of the potential barriers around the dots. The capture time is almost independent on the electric field up to(More)
We study the effect of side contacts on plasma oscillations in two-dimensional (2D) electron systems by numerical simulation. Our model is based on the kinetic electron transport equation and the self-consistent Poisson equation. We find that the contacts absorb the energy of plasma oscillations excited in the 2D electron channel and consequently this(More)
We analyze the effect of doping on photoelectron kinetics in quantum dot [QD] structures and find two strong effects of the built-in-dot charge. First, the built-in-dot charge enhances the infrared [IR] transitions in QD structures. This effect significantly increases electron coupling to IR radiation and improves harvesting of the IR power in QD solar(More)
We study plasma waves in a high-electron-mobility transistor (HEMT) structure by numerical simulation using the kinetic electron transport model. We find that the plasma waves in the gated section of the channel can damp even without the electron collisions with impurities and phonons. The damping is related to the thermal spread of the electron velocity.(More)
We calculate the energy dispersion relations in Si quantum wells (QW), E(k2D), and quantum wires (QWR), E(k1D), focusing on the regions with negative effective mass (NEM) in the valence band. The existence of such NEM regions is a necessary condition for the current oscillations in ballistic quasineutral plasma in semiconductor structures. The frequency(More)
Using Monte-Carlo method, we simulate kinetics and transport of electrons in different types of InAs/GaAs quantum-dot infrared photodetectors. Our simulation program exploits Γ-L-X model of the conduction band of semiconductor and it includes three major types of electron scattering on: 1) acoustic phonons, 2) polar optical phonons, and 3) intervalley(More)
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