Detection of single charges and their generation-recombination dynamics in Si nanowires at room temperature

Detection of single electrons and single holes is demonstrated at room temperature in Si nanowire transistors using an electron-hole (e-h) system. Photogenerated carriers are stored in a quantum dot electrically formed in a Si wire by a front gate. The stored charges affect the current of the other type of carriers that flow along the bottom of the Si wire. The linear photoresponce of single-charge generation is observed. It is revealed that the recombination occurs by a bimolecular process, suggesting that it is due to the e-h interband transition. These results open up the possibility of developing single-photon devices with this system.