The impact of dopant atoms in transistor functionality has significantly changed over the past few decades. In downscaled transistors, discrete dopants with uncontrolled positions and number induce fluctuations in device operation. On the other hand, by gaining access to tunneling through individual dopants, a new type of devices is developed: dopant-atom-based transistors. So far, most studies report transport through dopants randomly located in

We present the density functional theory calculations of the binding energy of the Phosphorus (P) donor electrons in extremely downscaled single P-doped Silicon (Si) nanorods. In past studies, the binding energy of donor electrons was evaluated for the Si nanostructures as the difference between the ionization energy for the single P-doped Si nanostructures and the electron affinity for the un-doped Si nanostructures. This definition does not take

The reduced dimensionality of present electronic devices brings along changes in the dopant distribution in the device channel, in which only a small number of dopants exist. Recent studies demonstrated that individual dopants strongly affect the electrical characteristics of nanoscale transistors. On the other hand, nanoscale pn junctions, building unit of more complex devices, have not been sufficiently studied from this viewpoint. In this work,

Nanoscale pn junctions have been investigated by Kelvin probe force microscopy and several particular features were found. Within the depletion region, a localized noise area is observed, induced by temporal fluctuations of dopant states. Electronic potential landscape is significantly affected by dopants with ground-state energies deeper than in bulk. Finally, the effects of light illumination were studied and it was found that the depletion region

We studied current-voltage characteristics of nanoscale pn diodes having the junction formed in a laterally patterned ultrathin silicon-on-insulator layer. At temperatures below 30 K, we observed random telegraph signal (RTS) in a range of forward bias. Since RTS is observed only for pn diodes, but not for pin diodes, one dopant among phosphorus donors or boron acceptors facing across the junction is likely responsible for potential changes affecting

Recently, the role of dopants in Si devices has been changing after a long and successful history in Si integrated circuit technology. The change can be seen as a transition from “bulk-type” dopants, with averaged potential, to “atom-type” dopants, with individual atomistic potential. Furthermore, dopant energy levels are modified by the effect of dielectric misfit with surrounding Si and the outside structure, which leads to the transformation

As electronic device dimensions are continuously reduced, new functions based on atomistic considerations can be implemented. Single-dopant transistors have been proposed based on a different mechanism as compared to conventional transistors, by making use of tunneling transport via individual dopant atoms located in nanoscale-channel transistors. However, typical dopants have shallow ground-state levels and thermally-activated transport becomes

Electronic potential measurements performed by low-temperature Kelvin probe force microscopy on silicon-on-insulator lateral nanoscale pn junctions are presented. The electronic potential landscape contains a region of enhanced potential induced by interdiffused dopants with deeper ground-state levels compared to bulk. The discrete dopant distribution can be observed in specific line profiles. In most line profiles, time-dependent potential fluctuations

Individual dopant atoms in silicon devices gain active roles as channel dimensions move into nanoscale from source to drain. A single donor can work as an atomic quantum dot, mediating single-electron tunneling transport. However, tunneling operation of single-donor transistors has so far been reported only at low temperatures below ~15 K, mainly because the tunnel barriers coupling the donor to the leads are too low. For higher-temperature operation,

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