We investigate the hole transport in p-channel field-effect transistors doped with boron, at low temperatures (6–28 K). In transistors with a relatively large dimension, we observe the acceptor-mediated hopping and carrier freezeout, both of which are strongly influenced by the gate bias. In nanoscale transistors, these features turn into single-charge tunneling, i.e., the trapping/detrapping of single holes by/from individual acceptors. The statistics of the appearance of the modulation in a few ten samples indicates that the number of acceptors is small, or even just one, indicating that what we have observed is single-charge-transistor operation by a single-acceptor quantum dot.
Ono, Y., Khalafalla, M., Nishiguchin, K., Takashina, K., Fujiwara, A., Horiguchi, S., Inokawa, H., & Takahashi, Y. (2008). Charge transport in boron-doped nano MOSFETs: Towards single-dopant electronics. Applied Surface Science, 254(19), 6252-6256. https://doi.org/10.1016/j.apsusc.2008.02.161