Strain and orientation modulated bandgaps and effective masses of phosphorene nanoribbons.

Han, Xiaoyu; Stewart, Henry Morgan; Shevlin, Stephen A; Catlow, C Richard A; Guo, Zheng Xiao · Nano Lett · 2014

basic_science · Level V

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Abstract

Passivated phosphorene nanoribbons, armchair (a-PNR), diagonal (d-PNR), and zigzag (z-PNR), were investigated using density functional theory. Z-PNRs demonstrate the greatest quantum size effect, tuning the bandgap from 1.4 to 2.6 eV when the width is reduced from 26 to 6 Å. Strain effectively tunes charge carrier transport, leading to a sudden increase in electron effective mass at +8% strain for a-PNRs or hole effective mass at +3% strain for z-PNRs, differentiating the (mh*/me*) ratio by an order of magnitude in each case. Straining of d-PNRs results in a direct to indirect band gap transition at either -7% or +5% strain and therein creates degenerate energy valleys with potential applications for valleytronics and/or photocatalysis.