Onise Sharia

TL;DR: This model reveals that mixed halide perovskites can be stabilized against phase separation by deliberately engineering carrier diffusion lengths and injected carrier densities, and explains observed non-linear intensity dependencies, as well as self-limited growth of iodide-rich domains.

TL;DR: In this article, the phase separation of halide ion movement in mixed halide films is tracked through excited-state behavior using emission and transient absorption spectroscopy tools, and the time scale with which such separation occurs under laser irradiation (405 nm, 25 mW/cm2 to 1.7 W/cm 2) as well as dark recovery.

TL;DR: In this article, various mechanisms for the Fermi level pinning of p-gate metals on HfO2 were analyzed in detail, and it was found that for FermI energies below the Si valence band, Hf O2 can oxidize Si by creating positively charged O vacancies.

Abstract: While the physics of the Schottky barrier is relatively well understood, much less is known about the band alignment at the insulator/insulator interface. As a model problem we study theoretically the band alignment at the technologically important $\mathrm{Si}{\mathrm{O}}_{2}∕\mathrm{Hf}{\mathrm{O}}_{2}$ interface using density functional theory. We report several different atomic level models of this interface along with their energies and electronic properties. We find that the valence band offset increases near linearly with the interfacial oxygen coordination, changing from $\ensuremath{-}2.0\phantom{\rule{0.3em}{0ex}}\mathrm{eV}\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}1.0\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$. For the fully oxidized interface the Schottky limit is reached. We propose a simple model, which relates the screening properties of the interfacial layer to the band offset. Our results may explain a somewhat confusing picture provided by recent experiments.

TL;DR: In this paper, the authors studied the band alignment at the semiconductor/insulator interface using density functional theory and found that the valence band offset increases near linearly with the interfacial oxygen coordination.