Abstract
Several conceptual nanodevices based on the four-atom-layer α- and β-Ge(2)Y(2) are constructed, and their electronic transport and photoelectronic properties are revealed by means of first-principles calculations. Our results demonstrate that the Ge(2)Y(2)-based p-n junction diodes show a great rectifying effect with high rectification ratio. Their p-i-n junction transistors show a field-effect behavior with better rectifying effect and stronger electronical anisotropy. Moreover, the Ge(2)Y(2) monolayers have strong photoelectronic response in the visible light region, displaying excellent photoelectronic properties in the photovoltaic materials and photoelectronic transistors. Our findings uncover the multi-functional features of four-atom-layer Ge(2)Y(2) monolayers, promising their extensive applications as candidates for future flexible semiconductor devices.