Figure 2.

(a) Illustration of the gated c-Al NW segment cross section in the vicinity of the Al–Ge nanojunction indicating the different material layers surrounding the NW. The according simulated distribution of the normalized electric field intensity (|E|²/|E₀|²) in direct vicinity to the Al–Ge interface of the fundamental mode is shown on the right. The individual field contributions |E_x|², |E_y|², |E_z|² are illustrated in Figure S2. Here, coupling of TM polarized light via the FGC (λ = 532 nm) is considered. The simulations show that the mode is bound to the c-Al NW even underneath the gate. The scale bar is 40 nm. (b) Schematic illustration of SPP propagation along the c-Al NW, SPP decay induced carrier injection into the Ge segment and the band-diagram with gate dependent barrier height. The green arrow schematically shows photoexcitation of the Ge segment and the associated electron–hole pair generation.