(Color online) The top and side views of the geometric structures of hydrogen terminated 〈112〉 SiNW with D of 3 nm, which has 216 Si and 60 H atoms marked Si216H60 NW. The big and small balls denote Si and H atoms, respectively. The numbers show the different (110) and (111) layers in the unit cell, respectively. ST, SB, SL, and SR represent surface layers surrounded SiNW, and H shows the terminated hydrogen layers. Each unit cell has six (112) layers. The electric bias creates an external electric field along the applied direction. V 111 is shown for representation of applied V on (111) surfaces.
(Color online) Electronic band structures of Si216H60 NW under (a) V 110 and (b) V 111 with V = 0.0, 0.5, 1.0, 1.5, 2.0, and 2.5 V. The dash lines show E F. The arrows label the indirect and direct characteristic of the bandgap.
The electron difference δ(2.0) of (110) and (111) layers for Si216H60 NW, where left and right shadow represent under V 110 and V 111, respectively. The numbers i denoting ith layer is defined in Fig. 1. Inset shows δ(V 110) of fifth (filled square) and sixth (filled circle) (110) layers and δ(V 111) of third (unfilled square) and fourth (unfilled circle) (111) layers. The straight lines are drawn to guide the eyes.
(Color online) (a) E g(D,V) functions of Si40H26, Si70H34, Si216H60 NWs with D = 1.3 nm (triangle), D = 1.7 nm (circle), and D = 3.0 nm (square), respectively, under V 110. Note that E g(D, V 111) = E g(D, V 110), here just shows the results of E g(D,V) under V 110 for representation. (b) E CBM and E VBM as a function with V. The straight lines are drawn to guide the eyes. Inset are the distributions of HOMO and LUMO under V 110 = 0 and V 110 = 1.5 V.
(Color online) DOS near E F under higher V = 3.0 (solid line), 4.0 (dashed line), 5.0 (dash dot line) V.
(Color online) DOS of CBE under (a) V 110 and (b) V 111. Consistent with Fig. 2, there are two peaks in the DOS in absence of V marked with (110) and (111). ΔE p is defined by the energy difference between the (110) and (111) peaks.
The comparison between the values calculated with HCTH and PW91 functionals.
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