LAUSR

Germanium selenide (GeSe) is an isoelectronic analogue of phosphorene, which has been studied widely in recent experiments. In this paper, we have investigated tunable electronic structures and transport properties of 2D and quasi-1D GeSe by using a self-consistent ab initio approach. The calculated band structures show stretching and compression in the zigzag direction and stretching in the armchair direction, and all can enlarge the band gap of 2D GeSe nanosheet. However, the compression in the armchair direction will reduce the band gap of the 2D GeSe nanosheet. In addition, appropriate compressions in both directions can change the 2D GeSe nanosheet from indirect band gap to direct band gap. When the 2D GeSe nanosheet is cut into a quasi-1D nanoribbon, the band structures can be modulated by the ribbon width and the passivation. The unpassivated zigzag GeSe nanoribbons are metals regardless of the ribbon width. The H-passivated zigzag GeSe nanoribbons are semiconductors with direct band gaps, and the ...