Nanometer-scale electronic devices are building blocks of future electronics. The function of these components is based on quantum-mechanical phenomena and therefore new modeling methods has to be developed to model properties of nano-devices. In this thesis one solution and implementation is presented.
In this thesis transport properties of the nano-devices are modeled using the density-functional theory. In the main part of the work electron densities and currents calculated using the Green's function method. The method enables the connection of the nanostructure to the semi-infinite leads by the open boundary conditions making finite-size effects small. Electron currents under finite bias conditions can also be calculated.
The use of the Green's function method is computationally heavy in comparison to the explicit wave-function methods. An important part of this thesis work is to choose efficient numerical methods and their implementation. The computer code created has one-, two- and three-dimensional versions so that different types of nanostructures can be modeled. The oneand two-dimensional versions use the effective mass approximation while the three-dimensional one uses nonlocal pseudopotential operators. The numerical implementation is done using the finite-element method with the so-called hp-elements.
The codes implemented are used to model magnetic resonance tunneling diodes, two-dimensional quantum wires, Na-atom chains and thin HfO2 layers.reviewe
