A single-photon detection using a Si-based two-dimensional (2D) multiple-tunnel-junction field-effect transistor (FET) is reported. The single photon is detected as a random telegraph signal (RTS) in the single-hole-tunneling current regime. The frequency of RTS events depends on the light wavelength and intensity, indicating that the RTS occurs due to the single-photon absorption in the Si dots forming the 2D multijunctions. Based on a Monte Carlo simulation using an equivalent circuit representing the 2D multijunction FET, the “on” state of RTS appears when the photogenerated charge in the dot sensitively shifts the current level, while the on state returns to the “off” state when the charged dot is neutralized. The simulation result also shows that the RTS is triggered not only by the charging of a dot near the current percolation path, but also by the charging of a dot distances away from the path due to the nature of the multijunction system, i.e., the long screening length of the charge-induced potential. These results open up the development of single-photon devices with 2D multijunction systems.

• Received 8 September 2005
• Publisher error corrected 17 January 2006

DOI:https://doi.org/10.1103/PhysRevB.73.045310