The dependence of electrical properties of rough and cylindrical Si nanowires (NWs) synthesized by diameter-controllable metal catalyst-assisted etching (MCE) on the size of the NW's diameter was demonstrated. Using a decal-printing and transfer process assisted by Al2O3 sacrificial layer, the Si NW field effect transistor (FET) embedded in a polyvinylphenol adhesive and dielectric layer were fabricated. As the diameter of Si NW increased, the mobility of FET increased from 80.51 to 170.95 cm(2)/V·s and the threshold voltage moved from -7.17 to 0 V because phonon-electron wave function overlaps, surface scattering, and defect scattering decreased and gate coupling increased as the ratio of surface-to-volume got reduced.