Detection of single holes generated by impact ionization in silicon

Abstract

We propose a method for the observation of the electron-initiated impact ionization process in Si, which is potentially capable of detecting individual impact ionization events. This method detects holes generated by the impact ionization with single charge sensitivity. We demonstrate the method at 8 K by detecting the chain of single holes generated for a constant electron-injection current with the injection-energy threshold close to the Si bandgap energy.

(Invited) Characteristics of Si Single-Electron Transistor under Illumination

“…Photo-excited carriers in Si quantum islands also show another interesting features such as single-electron CCD [20] where electrons and holes exist in the same island at the same time. In a SET, when a few holes generated by photo-excitation are trapped in the one side of the SET island under the vertical electric field, the number of trapped holes is detected by the electron current flowing through the other side of the island [21][22][23][24][25]. Since the number of the electrons in the SET island determines the transport characteristics, extra holes reduces the effective total number of electrons and make it possible to show the current peak at the lower gate voltage than that of the first peak as if the number of electrons was negative.…”