Figure 1. Fabrication of materials library.

(a) Schematic diagram showing the co-sputtering deposition. Material libraries, Zr-Cu-Al-Ag in the present study, can be prepared by sputtering from four elemental targets. Patched films can be obtained by attaching a physical mask onto Si substrate. Tilting of sputtering guns leads to different target-to-substrate distance which results in decreasing incoming flux across the substrate from near to far away from target, so that a composition gradient can be realized during deposition. (b) Appearance of as-deposited materials library. (c) Appearance of material library for antibacterial activity measurement. In (b,c), the relative positions of sputtering targets are indicated.