Edge modified zigzag GeS nanoribbon devices with tunable electronic properties and significant negative differential resistance effect: A first principle study

Using density functional theory (DFT) in combination with non-equilibrium Green's function (NEGF), we study the effects of edge modification on the structural, electronic, and transport properties of zigzag germanium sulphide nanoribbons (ZGeSNRs). Two different types of modification by H, F, and Cl atoms are considered, i.e., the unilateral edge modification (Ge or S edge) and the bilateral edge modification. The addition of modification atoms eliminates the dangling bonds at the edges and enhances the stability in general though the edge structure may be significantly modulated. The unilateral edge modifications do not change the metallic characteristics of ZGeSNRs but the bilateral edge modifications make them semiconductor. In addition, structures with one half-filled energy band separated from other bands can be realized to obtain strong negative differential resistance effects. A maximal peak-to-valley current ratio of 1.01×105 in the bias range 0.49–1.07 V is predicted in a H modified ZGeSNR, which should be promising for applications in low power and high performance nanoelectronic devices.