Investigation of electronic property modulation driven by strain in monolayer tellurium

Density functional theory (DFT) calculations have been employed to systematically investigate the strain-modulated electronic properties of monolayer tellurium. The results demonstrate that at zero strain gamma-phase monolayer tellurium is found to be more energetically favorable than either the alpha-phase or beta-phase which were fabricated through molecular-beam epitaxy. All studied phases are found to exhibit semiconductor characteristics, of which alpha- and gamma-phases possess indirect band gaps whereas beta phase is a direct band gap semiconductor. It is also found that the resulting band gap values approach zero at a large strain regime for all systems and the effective mass of electron and hole can be effectively modified by biaxial strain as well. These findings extend the knowledge on two-dimensional tellurium and provide potential applications in electronic devices.