First-principles ionized-impurity scattering and charge transport in doped materials

Abstract

Scattering of carriers with ionized impurities governs charge transport in doped semiconductors. However, electron interactions with ionized impurities cannot be fully described with quantitative first-principles calculations, so their understanding relies primarily on simplified models. Here we show an ab initio approach to compute the interactions between electrons and ionized impurities or other charged defects. It includes the shortand long-range electron-defect (e-d) interactions on equal footing and allows for efficient interpolation of the e-d matrix elements. We combine the e-d and electron-phonon interactions in the Boltzmann transport equation to compute the carrier mobilities in doped silicon over a wide range of temperature and doping concentrations, seamlessly spanning the defect-and phonon-limited transport regimes. The individual contributions of the defect-and phonon-scattering mechanisms to the carrier relaxation times and mean-free paths are analyzed. Our method provides a powerful tool to study electronic interactions in doped materials. It broadens the scope of first-principles transport calculations, enabling studies of a wide range of doped semiconductors and oxides with application to electronics, energy, and quantum technologies.

Ab initio calculation of carrier mobility in semiconductors including ionized-impurity scattering

“…Mobilities are then obtained by solving the ab initio Boltzmann transport equation (aiBTE) [26]. The first study of ionized-impurity scattering from first principles was reported by Restrepo and Pantelides [5], and more recent, state-of-the-art calculations have been reported by Lu and coworkers [14]. In this latter work, the authors find good agreement between calculated mobilities and experimental data for silicon.…”

“…This approach was pursued in Refs. [5] and [14], but it carries the disadvantage that one needs to compute defect energetics prior to mobility calculations, and then perform rotational averages to account for the randomness of the impurity orientation. Our simpler approach is useful for systematic transport calculations when detailed knowledge of the atomic-scale structure of impurities is lacking, and can be made more accurate by incorporating dipole and quadrupole terms along the lines of Refs.…”

“…The past decade has seen numerous developments in first-principles calculations of phonon-limited charge transport coefficients such as the electrical conductivity in metals, and the drift and Hall mobilities in semiconductors [5][6][7][8][9][10][11]. More recently, several groups turned their attention to ab initio calculations of additional scattering mechanisms [5,[12][13][14][15][16]. Among the various mechanisms, impurity scattering is of particular interest since ionized donors and acceptors are ubiquitous in high-purity doped semiconductors, and intrinsic point defects are unavoidable in all other materials [17][18][19].…”

High-field charge transport and noise in p -Si from first principles

“…2D materials including graphene [14][15][16][17] and MoS 2 [9,[16][17][18][19], and others [1]. The approach continues to develop, with advances in the ab-initio description of two-phonon scattering [20], neutral and ionized impurity scattering [21,22], quadrupole interactions [23,24], and others [25,26].…”

Assessing the quality of relaxation-time approximations with fully-automated computations of phonon-limited mobilities

“…In principle, a fully ab initio description of transport phenomena should take into account several different scattering channels due to the interaction with, e.g., phonons, electrons, crystalline defects, ionized impurities, and even grain-boundaries in the case of polycrystalline samples. In practice, most of the studies reported so far have focused on the contribution due to e-ph scattering, while other effects such as the scattering by ionized impurities have been introduced either in an indirect way via semi-empirical models [11,12] or via additional ab initio calculations [13][14][15]. At the level of the e-ph scattering, the predictive power of ab initio methods has recently been quantified by estimating the impact of various effects such as spin-orbit coupling or many-body corrections to the e-ph vertex or effective masses in the case of silicon [12].…”