Disordered Si:P nanostructures as switches and wires for nanodevices

Abstract

Atomically precise placement of dopants in Si permits creating substitutional P nanowires by design. High-resolution images show that these wires are few atoms wide with some positioning disorder with respect to the substitutional Si structure sites. Disorder is expected to lead to electronic localization in one-dimensional (1D) -like structures. Experiments, however, report good transport properties in quasi-1D P nanoribbons. We investigate theoretically their electronic properties using an effective single-particle approach based on a linear combination of donor orbitals (LCDO), with a basis of six orbitals per donor site, thus keeping the ground state donor orbitals' oscillatory behavior due to interference among the states at the Si conduction band minima. Our model for the P positioning errors accounts for the presently achievable placement precision allowing to study the localization crossover. In addition, we show that a gate-like potential may control its conductance and localization length, suggesting the possible use of Si:P nanostructures as elements of quantum devices, such as nanoswitches and nanowires. arXiv:1902.01332v1 [cond-mat.mes-hall]

Conductivity and size quantization effects in semiconductor δ-layer systems

“…The electronic structure and conductive properties of Si:P δ -layer systems have been a subject of previous studies based on either effective mass [14][15][16][17], tight-binding [18][19][20][21][22], den-FIG. 1.…”

Conductivity and size quantization effects in semiconductor $$\delta$$-layer systems

“…devices with sub-20 nm physical gate/channel lengths and/or sub-20 nm widths, that could compete with the future CMOS, the conductive properties of such systems are expected to exhibit a strong influence of size quantization effects. At the same time, experimental assessment of the conductivity of δ-layer systems is typically performed using Hall measurements on samples of macroscopic dimensions ( > 1 µm) 5,[11][12][13] .The electronic structure and conductive properties of Si:P δ-layer systems have been a subject of previous studies based on either effective mass [14][15][16][17] , tight-binding [18][19][20][21][22] , density functional theory [23][24][25] formalisms or semiclassical Boltzmann theory 26 . Recently it has been demonstrated in [15][16][17] that to accurately extract the conductive properties of highly-conductive, highly-confined systems, an open-system quantum-mechanical analysis is necessary.…”

“…The electronic structure and conductive properties of Si:P δ-layer systems have been a subject of previous studies based on either effective mass [14][15][16][17] , tight-binding [18][19][20][21][22] , density functional theory [23][24][25] formalisms or semiclassical Boltzmann theory 26 . Recently it has been demonstrated in [15][16][17] that to accurately extract the conductive properties of highly-conductive, highly-confined systems, an open-system quantum-mechanical analysis is necessary.…”