Photon-Induced Random Telegraph Signal Due to Potential Fluctuation of a Single Donor–Acceptor Pair in Nanoscale Si p–n Junctions

We study the photoresponse of Si nanoscale p–n and p–i–n diodes. As a result, we find a photon-sensitive multilevel random telegraph signal (RTS) in p–n diodes, but not in p–i–n diodes. From this fact and analysis of current jumps in the RTS, the multilevel RTS is ascribed to single photocarrier charging and discharging in a donor–acceptor pair in the depletion region. Thus, it is found that a donor–acceptor pair plays an important role in p–n junctions, while, according to our previous report, a single donor (acceptor) works as an electron (hole) trap in junctionless field-effect transistors.