In a single-step synthesis, a ~40 nm wide, 5 um long straight nano- silicon wire was grown together with two micro-sized silicon crystal balls. Bearing a nano- Si bridge as the functional ‘channel’ and two Si balls as the pads, this structure is potentially similar to a silicon transistor (essentially a tunable resistor), which has strikingly changed our lives. Having a feature size similar to commercial transistors fabricated using state-of-the-art technologies, our all-silicon nano-bridge may also find its applications in solar cells, and could see itself being used in future electronic devices, such as ipods, laptops, automobiles, and so on.