Band gap engineering of monolayer ZrGeTe4 via strain: A first-principles study

Modulating the bandgap of two-dimensional (2D) semiconductors is of particular importance for electronics, optoelectronics, and sensors applications in the nanoscale. Here, based on first-principles calculations, we report the modulation of electronic, mechanical, and optical properties of a ternary transition metal chalcogenide ZrGeTe4 monolayer with the applied external strain. The perfect 2D ZrGeTe4 crystal is a semiconductor with a direct bandgap of 1.21 eV, exhibiting anisotropic elastic and optical response. Both external compression and tensile strain can reduce its bandgap linearly, resulting in the modulation of its optical absorption edge. In particular, a semiconductor-to-metal transition observed in ZrGeTe4 monolayer under a compression strain. The flexibility and significantly strain-tunable electronics properties in 2D ZrGeTe4 monolayer render its great potential in the nanoscale electronic and optoelectronic applications.