Comparison of basis sets for efficient Ab-initio modeling of semiconductors

Abstract

Germanium faces several technological hurdles in replacing silicon and fulfilling its promise as an alternate channel material; namely, low dopant activation, gate stack interface quality, and high contact resistivity for n-Ge. Ab-initio methods could help to address some of these challenges by providing fundamental insight. However, these calculations often tend to be too computationally heavy to be practically useful. In this work, we compare the speed and accuracy of density functional theory (DFT) calculations on the NiGe/Ge Schottky contact using various localized basis sets, and a standard plane wave solver as a complementary DFT solver to affirm on the accuracy. We first compare Atomistix Tool Kit (ATK), a localized-basis DFT solver, to the popular plane wave based Vienna Ab-initio Software Package (VASP) to show that the localized basis sets while being faster, can also match plane wave for accuracy; thereafter, we compare different localized basis sets within ATK.