Abstract: A molecule sensor included in a molecule sensor device has a semiconductor substrate, a bottom gate, a source portion, a drain portion, and a nano-scale semiconductor wire. The bottom gate is for example a poly-silicon layer formed on the semiconductor substrate and electrically insulated from the semiconductor substrate. The source portion is formed on the semiconductor substrate and insulated from the semiconductor substrate. The drain portion is formed on the semiconductor substrate and insulated from the semiconductor substrate. The nano-scale semiconductor wire is connected between the source portion and the drain portion, formed on the bottom gate, insulated from the bottom gate, and has a decoration layer thereon for capturing a molecular. The source portion, drain portion, and nano-wire semiconductor wire are for example another poly-silicon layer. The bottom gate receives a specified voltage to change an amount of surface charge carriers of the nano-scale semiconductor wire.