Fig. 1. Structural diagrams of planar single-junction and double-junction hot-electron devices and injection efficiency. (a) Structural diagram of planar single-junction hot-electron device; (b) injection efficiency ${\eta }_{\mathrm{i}\mathrm{n}\mathrm{j}}$of hot-electron calculated by Fowler’s theory and Monte Carlo simulation; ${\eta }_{\mathrm{i}\mathrm{n}\mathrm{j}}$ varying with incident photon energy $E_{\mathrm{p}\mathrm{h}}$ and thickness t of Au of (c) single-junction and (d) double-junction hot-electron devices; (e) structural diagram of planar double-junction hot-electron device; injection efficiency spectra at different thicknesses of Au of (f) single-junction and (g) double-junction hot-electron devices; (h) injection efficiency ratio of double- and single-junction devices at different thicknesses of Au

Fig. 2. Structural diagrams and hot-electron distributions of hot-electron devices with different structures. (a)(b) Cylindrical structure; (c)(d) single-junction nanowire core-shell structure; (e)(f) double-junction nanowire core-shell structure

Fig. 3. Injection efficiency of single-junction core-shell nanowire structure when considering electron scattering and without considering electron scattering. Injection efficiency of single-junction core-shell nanowire structure for （a）different metallic film thicknesses and (b) different nanowire radii without considering electron scattering；(c) injection efficiency as a function of $t$ and$R_{\mathrm{T}\mathrm{i}{\mathrm{O}}_{\mathrm{2}}}$for $E_{\mathrm{p}\mathrm{h}}=\mathrm{2}\mathrm{e}\mathrm{V}$； (d)‒(f) injection efficiency of hot electrons corresponding to Figs. 3(a)‒(c) when considering electron scattering

Fig. 4. Injection efficiency of double-junction core-shell nanowire structure when considering electron scattering and without considering electron scattering. Injection efficiency of double-junction core-shell nanowire structure for （a）different metallic film thicknesses and (b) different nanowire radii without considering electron scatterings； (c) injection efficiency as a function of $t$ and$R_{\mathrm{T}\mathrm{i}{\mathrm{O}}_{\mathrm{2}}}$for $E_{\mathrm{p}\mathrm{h}}=\mathrm{2}\mathrm{e}\mathrm{V}$； (d)‒(f) injection efficiency of hot electrons corresponding to Figs. 4(a)‒(c) when considering electron scattering

Fig. 5. Injection efficiency of inner and outer Schottky junction varying with $R_{\mathrm{T}\mathrm{i}{\mathrm{O}}_{\mathrm{2}}}$and t for $E_{\mathrm{p}\mathrm{h}}$ of 2, 2.5, and 3 eV in double-junction core-shell nanowire structures. （a）‒（c） Injection efficiency varying with $R_{\mathrm{T}\mathrm{i}{\mathrm{O}}_{\mathrm{2}}}$ when $t=\mathrm{10}\mathrm{n}\mathrm{m}$；（d）‒（f） injection efficiency varying with t when $R_{\mathrm{T}\mathrm{i}{\mathrm{O}}_{\mathrm{2}}}=\mathrm{50}\mathrm{n}\mathrm{m}$