QuantumWise will be at the MRS Fall Meeting in Boston, Massachusetts on November 27 - December 1. You can meet Umberto and Sam at booth #823. Moreover, Umberto will give an oral presentation, please see below.
Title: General Atomistic Approach for Modeling Metal-Semiconductor Interfaces Using Density Functional Theory and Non-Equilibrium Green's Functions
Paper Number: TC1.4.08
Presentation Date: November 30, 2016 from 8:30 AM to 12:00 PM
Room: Hynes, Level 3, Room 305
"Metal-semiconductor (M-SC) contacts play a pivotal role in a broad range of technologically relevant devices. Still, their characterization at the atomic-scale remains a delicate issue. One of the reasons is that the present understanding relies either on simplified analytical models often parametrized using experimental data, or on electronic structure simulations describing the interface using simple slab calculations. Here we propose a general strategy to model realistic M-SC interfaces by using density functional theory (DFT) in combination with the non-equilibrium Green's function (NEGF) method as implemented in the Atomistix ToolKit (ATK) simulation software. An accurate description of both sides of the interface is achieved by using a meta-GGA functional optimally tuned to reproduce the SC measured band-gap, and a spatially dependent effective scheme to account for the presence of doping in the SC side. Compared to previous computational methods, the present approach has the important 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 to describe its properties."