Figure 3

(a) Simulated spectral responsivity as a function of the NP diameter d_NP for a complete device as shown in Fig. 1. The overlay shows the photonic modes as described by Eq. 1. The points indicate the maxima of the Gaussian functions used to fit the measured responsivities shown in Fig. 5. The orientation of the incident field was chosen to be E₀‖(x + y). (b)–(e) Cross-sectional images of the absolute value of the electric field distribution inside NP-PDs with d_NP = 300 nm at incident wavelengths of λ = 760 nm (b) and λ = 976 nm (c) (corresponding to absorption maxima, see Fig. 6a for n = 1.0) and NP-PDs with d_NP = 540 nm at λ = 1128 nm (d) and λ = 1376 nm (e). The orientation of the incident field for (b)-(e) is E₀‖x. The horizontal plane in (b)–(e) is approximately 250 nm below the top Si-Ge interface.