Supplementary Materials Supplementary Materials for Electrical and optical interconnection for mechanically stacked multi- junction solar cells mediated by metal nanoparticle arrays Hidenori Mizuno, Kikuo Makita, and Koji Matsubara Research Center for Photovoltaic Technologies, National Institute of Advanced Industrial Science and Technology, Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan Email: [email protected] S1 Supplementary Materials 1. EDX spectra of the GaAs/Pd/InP stacking (a) 200 O (K) 180 Pd (L) 160 Counts In (L) 140 P (K) 120 Ga (K) As (K) 100 80 60 40 20 0 0 10 20 30 40 Distance (nm) (b) P In O Pd As Ga 10 nm Figure S1. (a) EDX spectra of the GaAs/Pd/InP stacking. (b) Superimpose of the spectra shown in (a) and the STEM image shown in the main text (Figure 2b). Oxygen peaks (blue line) were observed at the GaAs/Pd and the Pd/InP interfaces, indicating the presence of oxide layers. S2 Supplementary Materials 2. Low-magnification STEM image of the GaAs/Pd/InP stacking Figure S2. STEM image of the GaAs/Pd/InP stacking. S3 Red arrows indicate the positions of Pd NPs.