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HL: Fachverband Halbleiterphysik

HL 36: Transport properties

HL 36.5: Vortrag

Donnerstag, 30. März 2023, 11:00–11:15, POT 151

Comprehensive model for the thermoelectric properties of two-dimensional carbon nanotube networks — •Aditya Dash, Dorothea Scheunemann, and Martijn Kemerink — Institute for Molecular Systems Engineering and Advanced Materials, Heidelberg University, Im Neuenheimer Feld 225, 69120 Heidelberg, Germany.

Networks of semiconducting single-walled carbon nanotubes (SWCNTs) are interesting thermoelectric materials due to the interplay between CNT and network properties. Here we present a unified model to explain the charge and energy transport in SWCNT networks. We used the steady-state master equation for the random resistor network containing both the intra- and inter-tube resistances, as defined through their 1D density of states that is modulated by static Gaussian disorder. The tube resistance dependence on the carrier density and disorder is described through the Landauer formalism. Electrical and thermoelectric properties of the network were obtained by solving Kirchhoffs laws through a modified nodal analysis, where we used the Boltzmann transport formalism to obtain the conductivity, Seebeck coefficient, and electronic contribution to the thermal conductivity. The model provides a consistent description of previously published experimental data for temperature and carrier density-dependent conductivities and Seebeck coefficients, with energetic disorder being the main factor explaining observed mobility upswing with carrier concentration. For lower disorder, the Lorentz factor obtained from simulation is in accordance with the Wiedemann-Franz law. Suppressed disorder and lattice thermal conductivity can be a key to higher zT.