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Tunneling in Systems of Coupled Dopant-Atoms in Silicon Nano-devices.

Moraru D, Samanta A, Tyszka K, Anh le T, Muruganathan M, Mizuno T, Jablonski R, Mizuta H, Tabe M - Nanoscale Res Lett (2015)

Bottom Line: One pathway to observe and characterize such fundamental operation is to focus on identifying isolated or coupled dopants in nanoscale silicon transistors, the building blocks of present electronics.We also discuss tunneling transport behavior based on the analysis of low-temperature I-V characteristics for devices representative for different regimes of doping concentration, i.e., different inter-dopant coupling strengths.This overview outlines the present status of the field, opening also directions toward practical implementation of dopant-atom devices.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronics and Materials Science, Faculty of Engineering, Shizuoka University, Shizuoka, Japan. moraru.daniel@shizuoka.ac.jp.

ABSTRACT
Following the rapid development of the electronics industry and technology, it is expected that future electronic devices will operate based on functional units at the level of electrically active molecules or even atoms. One pathway to observe and characterize such fundamental operation is to focus on identifying isolated or coupled dopants in nanoscale silicon transistors, the building blocks of present electronics. Here, we review some of the recent progress in the research along this direction, with a focus on devices fabricated with simple and CMOS-compatible-processing technology. We present results from a scanning probe method (Kelvin probe force microscopy) which show direct observation of dopant-induced potential modulations. We also discuss tunneling transport behavior based on the analysis of low-temperature I-V characteristics for devices representative for different regimes of doping concentration, i.e., different inter-dopant coupling strengths. This overview outlines the present status of the field, opening also directions toward practical implementation of dopant-atom devices.

No MeSH data available.


Single-electron tunneling via a cluster of several strongly-coupled donors. a Schematic illustration of a QD formed by several strongly-interacting P-donors; the QD exhibits a molecular-like energy spectrum. b First-principles calculation of projected density of states (PDOS) spectrum for a 5-nm-long Si nanostructure containing a small number (3) of interacting P-donors. PDOS is plotted by different colors at the location of different P-donors, indicating the splitting of the ground state energy levels. c Low-temperature ID-VG characteristics, exhibiting a number of consecutive current peak envelopes (as marked by dashed boxes). Each current peak envelope contains steps (inflections) as modulations of the tunneling current due to discrete energy states induced by strongly coupled P-donors [19]
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Fig6: Single-electron tunneling via a cluster of several strongly-coupled donors. a Schematic illustration of a QD formed by several strongly-interacting P-donors; the QD exhibits a molecular-like energy spectrum. b First-principles calculation of projected density of states (PDOS) spectrum for a 5-nm-long Si nanostructure containing a small number (3) of interacting P-donors. PDOS is plotted by different colors at the location of different P-donors, indicating the splitting of the ground state energy levels. c Low-temperature ID-VG characteristics, exhibiting a number of consecutive current peak envelopes (as marked by dashed boxes). Each current peak envelope contains steps (inflections) as modulations of the tunneling current due to discrete energy states induced by strongly coupled P-donors [19]

Mentions: A schematic potential profile induced by several interacting P-donors in such selectively-doped SOI-FETs is shown in Fig. 6a. A relatively complex energy spectrum is expected due to interactions among a number of P-donors located closely to each other. This model is basically supported by first-principles simulations of silicon nanostructures containing a small number of P-donors [19, 36]. The results, such as the example shown in Fig. 6b, suggest that there is a certain correlation between the number of P-donors coupled together and the energy spectrum of the silicon nanostructures. Further evidence has been obtained from the analysis of KPFM measurements correlated with simulations of dopant-induced potential landscapes [25, 26]. Typical ID-VG characteristics for devices of this type are shown in Fig. 6c for a narrow range of low temperatures. Different than the cases for lower-concentration devices, we can observe current peak envelopes, rather than isolated current peaks. These current peak envelopes exhibit a more complex sub-structure, with a number of inflections and sub-peaks incorporated within the envelopes. As described above, these features can be ascribed to tunneling transport through a complex energy spectrum of the transport-QD. Such a complex spectrum is likely induced by the strong interactions among a number of closely placed P-donors.Fig. 6


Tunneling in Systems of Coupled Dopant-Atoms in Silicon Nano-devices.

Moraru D, Samanta A, Tyszka K, Anh le T, Muruganathan M, Mizuno T, Jablonski R, Mizuta H, Tabe M - Nanoscale Res Lett (2015)

Single-electron tunneling via a cluster of several strongly-coupled donors. a Schematic illustration of a QD formed by several strongly-interacting P-donors; the QD exhibits a molecular-like energy spectrum. b First-principles calculation of projected density of states (PDOS) spectrum for a 5-nm-long Si nanostructure containing a small number (3) of interacting P-donors. PDOS is plotted by different colors at the location of different P-donors, indicating the splitting of the ground state energy levels. c Low-temperature ID-VG characteristics, exhibiting a number of consecutive current peak envelopes (as marked by dashed boxes). Each current peak envelope contains steps (inflections) as modulations of the tunneling current due to discrete energy states induced by strongly coupled P-donors [19]
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4582038&req=5

Fig6: Single-electron tunneling via a cluster of several strongly-coupled donors. a Schematic illustration of a QD formed by several strongly-interacting P-donors; the QD exhibits a molecular-like energy spectrum. b First-principles calculation of projected density of states (PDOS) spectrum for a 5-nm-long Si nanostructure containing a small number (3) of interacting P-donors. PDOS is plotted by different colors at the location of different P-donors, indicating the splitting of the ground state energy levels. c Low-temperature ID-VG characteristics, exhibiting a number of consecutive current peak envelopes (as marked by dashed boxes). Each current peak envelope contains steps (inflections) as modulations of the tunneling current due to discrete energy states induced by strongly coupled P-donors [19]
Mentions: A schematic potential profile induced by several interacting P-donors in such selectively-doped SOI-FETs is shown in Fig. 6a. A relatively complex energy spectrum is expected due to interactions among a number of P-donors located closely to each other. This model is basically supported by first-principles simulations of silicon nanostructures containing a small number of P-donors [19, 36]. The results, such as the example shown in Fig. 6b, suggest that there is a certain correlation between the number of P-donors coupled together and the energy spectrum of the silicon nanostructures. Further evidence has been obtained from the analysis of KPFM measurements correlated with simulations of dopant-induced potential landscapes [25, 26]. Typical ID-VG characteristics for devices of this type are shown in Fig. 6c for a narrow range of low temperatures. Different than the cases for lower-concentration devices, we can observe current peak envelopes, rather than isolated current peaks. These current peak envelopes exhibit a more complex sub-structure, with a number of inflections and sub-peaks incorporated within the envelopes. As described above, these features can be ascribed to tunneling transport through a complex energy spectrum of the transport-QD. Such a complex spectrum is likely induced by the strong interactions among a number of closely placed P-donors.Fig. 6

Bottom Line: One pathway to observe and characterize such fundamental operation is to focus on identifying isolated or coupled dopants in nanoscale silicon transistors, the building blocks of present electronics.We also discuss tunneling transport behavior based on the analysis of low-temperature I-V characteristics for devices representative for different regimes of doping concentration, i.e., different inter-dopant coupling strengths.This overview outlines the present status of the field, opening also directions toward practical implementation of dopant-atom devices.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronics and Materials Science, Faculty of Engineering, Shizuoka University, Shizuoka, Japan. moraru.daniel@shizuoka.ac.jp.

ABSTRACT
Following the rapid development of the electronics industry and technology, it is expected that future electronic devices will operate based on functional units at the level of electrically active molecules or even atoms. One pathway to observe and characterize such fundamental operation is to focus on identifying isolated or coupled dopants in nanoscale silicon transistors, the building blocks of present electronics. Here, we review some of the recent progress in the research along this direction, with a focus on devices fabricated with simple and CMOS-compatible-processing technology. We present results from a scanning probe method (Kelvin probe force microscopy) which show direct observation of dopant-induced potential modulations. We also discuss tunneling transport behavior based on the analysis of low-temperature I-V characteristics for devices representative for different regimes of doping concentration, i.e., different inter-dopant coupling strengths. This overview outlines the present status of the field, opening also directions toward practical implementation of dopant-atom devices.

No MeSH data available.