English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Monolayer MoS$_2$ has emerged as an interesting material for nanoelectronicand optoelectronic devices. The effect of substrate screening and defects onthe electronic structure of MoS$_2$ are important considerations in the designof such devices. Here, we present ab initio density functional theory (DFT) andGW calculations to study the effect of substrate screening on the quasiparticleband gap and defect charge transition levels (CTLs) in monolayer MoS$_2$. Wefind a giant renormalization to the free-standing quasiparticle band gap by 350meV and 530 meV in the presence of graphene and graphite as substrates,respectively. Our results are corroborated by recent experimental measurementson these systems using scanning tunneling spectroscopy and photoluminescenceexcitation spectroscopy. Sulfur vacancies are the most abundant native defectsfound in MoS$_2$. We study the CTLs of these vacancies in MoS$_2$ using theDFT+GW formalism. We find (+1/0) and (0/-1) CTLs appear in the pristine bandgap of MoS$_2$. Substrate screening results in renormalization of the (0/-1)level, with respect to the valence band maximum (VBM), by the same amount asthe gap. This results in the pinning of the (0/-1) level about $\sim$500 meVbelow the conduction band minimum for the free-standing case as well as in thepresence of substrates. The (+1/0) level, on the other hand, lies less than 100meV above the VBM for all the cases.

Substrate screening effects on the quasiparticle band gap and defect charge transition levels in MoS$_2$