Bandgap engineering of PbTe ultra-thin layers by surface passivations

Abstract

We calculate the electronic structures of the PbTe (1 1 1) ultra-thin films by performing the first-principles calculations. The PbTe (1 1 1) ultra-thin films possess direct or indirect band gaps depending sensitively on surface passivations with hydrogen or halogen atoms, and the band gaps depend sensitively on the passivation elements. The bandgaps of PbTe (1 1 1) ultra-thin films with hydrogen passivations can be tuned from 15 meV to 65 meV by applying external strains, making PbTe ultra-thin films promising candidates for optoelectronic device applications in terahertz regime.

Modulation of the electronic property of hydrogenated 2D tetragonal Ge by applying external strain

“…[23][24][25] PbTe lms passivated with H atoms are semiconductors with a direct band gap of 0.015 eV, and the direct band gap can be tuned from 0.015 eV to 0.065 eV under external strain. 26 The tensile strain can tune the band gap of GaN monolayer in the broad range of 4.44-2.27 eV. 22 The 2D tetragonal XBi (X ¼ Si, Ge, Sn) undergo a transition from a direct to indirect band gap or an indirect band gap semiconductor to metal by applying biaxial strain.…”