The effects of layer thickness and periodicity on thermoelectric properties of Si/Ge superlattice materials are studied through a non-equilibrium Green’s function (NEGF) computational approach. Results show an independence of Seebeck coefficient for increasing the number of superlattice periods. Additionally, a critical layer thickness is obtainable to achieve a favorable transmission spectrum ...

Using the non-equilibrium Green's function (NEGF) formalism within the sequential regime, we studied ultrahigh spin thermopower and pure spin current in single-molecule magnet(SMM), which is attached to nonmagnetic metal wires with spin bias and angle (θ) between the easy axis of SMM and the spin orientation in the electrodes. A pure spin current can be generated by tuning the gate voltage and ...

The use of ensemble Monte Carlo (EMC) methods for the simulation transport in semiconductor devices has become extensive over past few decades. This method allows utilizing particles while addressing full physics within device, leaving computational difficulties to computer. More recently, study quantum mechanical effects devices, which also strongly affect carrier itself, have important. While...

Carrier transport in modern nanoelectronic devices involves physical scales which require quantum descriptions. Basic quantum mechanics describes systems determined by Hamiltonian state vectors |Ψ>, which provide the spatial and time dependences of the physical observables. A pure state density operator |Ψ><Ψ| as obtained by a single state vector contains the most complete information about the...

We have included Shockley-Read-Hall (SRH) generation/recombination in Non-equilibrium Green’s function (NEGF) calculations via a multiphonon relaxation model. The model has been used to study how the presence of defects affects current–voltage characteristics GaAs p-i-n diodes, and an InGaAs tunnel diode. Regarding we show that SRH is responsible for ideality factors approaching theoretical val...

This paper aims to investigate the spin dependent transport properties in hybrid nanoribbons, using non equilibrium Greens function method. The effects of temperature gradient between left and right leads, ferromagnetic exchange field, local external electric fields are also included. results show that up down currents produced flow opposite directions with almost equal magnitudes. evidently sh...

We have applied two different simulation models for the stationary carrier transport and optical gain analysis in resonant phonon depopulation THz Quantum Cascade Lasers (QCLs), based on the semiclassical ensemble Monte Carlo (EMC) and fully quantum mechanical non-equilibrium Green’s functions (NEGF) method, respectively. We find in the incoherent regime near and above the threshold current a q...

In this thesis electronic transport through nanoscale devices is modeled by means of quantum physics. Moving from ballistic transport towards a detailed description of electron-phonon scattering, the used formalism changes from wave functions to the non-equilibrium Green’s functions (NEGF). The simulation framework consists of the quantum mechnical simulator SIMNAD, which was developed at the I...

Adsorption of the toxic gas molecules carbon monoxide (CO), dioxide (CO2) and ammonia (NH3 ) on edge N-doped sawtooth penta-graphene nanoribbons (N:SSPGNRs) was studied using first-principles methods. Basing our study density functional theory (DFT), we investigated adsorption configurations, energy, charge transfer, electronic properties CO-, CO2 - NH3- adsorbed ontoN:SSPGNRs. We found that CO...