We synthesize and analyze Ag-doped ZnO (SZO) nanowires (NWs) via a vapor-liquid-solid mechanism in a physical vapor deposition. The process condition for the SZO NW formation is optimized by adjusting the kinetic energy and the flux of the laser-ablated particles by hot-wall control. Electron microscopes ensure excellent morphologies of the doped NWs obtained. We confirm p-type doping effects, with low temperature photoluminescence used to trace the A(0)X peak. We realize diodes with all-ZnO-based p-n junctions of SZO NWs and Ga-doped ZnO thin films, resulting in asymmetric I-V characteristics with the turn on voltage of 3.8 V.