Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 83: Heterostructures and Interfaces
O 83.13: Vortrag
Donnerstag, 10. März 2016, 13:00–13:15, H17
General DFT+NEGF approach for modeling metal-semiconductor interfaces — •daniele stradi1, umberto martinez pozzoni2, anders blom2, mads brandbyge1, and kurt stokbro2 — 1DTU Nanotech, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark — 2QuantumWise A/S, Freubjergvej 3, Postbox 4, DK-2100 Copenhagen, Denmark
Metal-semiconductor (M-SC) contacts play a pivotal role in a broad range of technologically relevant devices. Still, their characterization remains a delicate issue, as the present understanding relies either on simplified analytical models [1], or on simulations describing the interface using simple slab models [2]. We model realistic M-SC interfaces by using the DFT+NEGF method as implemented in the Atomistix ToolKit (ATK) simulation software [3]. An accurate description of the interface is achieved by using a meta-GGA functional [4], and an effective scheme to account for the presence of doping in the SC side. The present approach has the advantages of (i) treating the system using the appropriate boundary conditions and (ii) allowing for a direct comparison between theory and experiments by simulating the I-V characteristics of the interface. We apply this methodology to an Ag/Si interface relevant for solar cell applications, and test the reliability of traditional strategies [1,2] to describe its properties [5]. [1] Physics of Semiconductor Devices: 3rd edition (Wiley, 2006); [2] Phys. Rev. B 35, 8154 (1987); [3] Atomistix ToolKit version 2015.0, QuantumWise A/S (www.quantumwise.com); [4] Phys. Rev. Lett. 102, 226401 (2009); [5] D. Stradi et al. In preparation