| 1. |
- Fan, Dingxun, et al.
(författare)
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Formation of long single quantum dots in high quality InSb nanowires grown by molecular beam epitaxy
- 2015
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3372 .- 2040-3364. ; 7:36, s. 14822-14828
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Tidskriftsartikel (refereegranskat)abstract
- We report on realization and transport spectroscopy study of single quantum dots (QDs) made from InSb nanowires grown by molecular beam epitaxy (MBE). The nanowires employed are 50-80 nm in diameter and the QDs are defined in the nanowires between the source and drain contacts on a Si/SiO2 substrate. We show that highly tunable QD devices can be realized with the MBE-grown InSb nanowires and the gate-to-dot capacitance extracted in the many-electron regimes is scaled linearly with the longitudinal dot size, demonstrating that the devices are of single InSb nanowire QDs even with a longitudinal size of similar to 700 nm. In the few-electron regime, the quantum levels in the QDs are resolved and the Lande g-factors extracted for the quantum levels from the magnetotransport measurements are found to be strongly level-dependent and fluctuated in a range of 18-48. A spin-orbit coupling strength is extracted from the magnetic field evolutions of a ground state and its neighboring excited state in an InSb nanowire QD and is on the order of similar to 300 mu eV. Our results establish that the MBE-grown InSb nanowires are of high crystal quality and are promising for the use in constructing novel quantum devices, such as entangled spin qubits, one-dimensional Wigner crystals and topological quantum computing devices.
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| 2. |
- Fan, Dingxun, et al.
(författare)
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Schottky barrier and contact resistance of InSb nanowire field-effect transistors
- 2016
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 27:27
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Tidskriftsartikel (refereegranskat)abstract
- Understanding of the electrical contact properties of semiconductor nanowire (NW) field-effect transistors (FETs) plays a crucial role in the use of semiconducting NWs as building blocks for future nanoelectronic devices and in the study of fundamental physics problems. Here, we report on a study of the contact properties of Ti/Au, a widely used contact metal combination, when contacting individual InSb NWs via both two-probe and four-probe transport measurements. We show that a Schottky barrier of height is present at the metal-InSb NW interfaces and its effective height is gate-tunable. The contact resistance () in the InSb NWFETs is also analyzed by magnetotransport measurements at low temperatures. It is found that in the on-state exhibits a pronounced magnetic field-dependent feature, namely it is increased strongly with increasing magnetic field after an onset field . A qualitative picture that takes into account magnetic depopulation of subbands in the NWs is provided to explain the observation. Our results provide solid experimental evidence for the presence of a Schottky barrier at Ti/Au-InSb NW interfaces and can be used as a basis for design and fabrication of novel InSb NW-based nanoelectronic devices and quantum devices.
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| 3. |
- Kang, Ning, et al.
(författare)
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Two-Dimensional Quantum Transport in Free-Standing InSb Nanosheets
- 2019
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 19:1, s. 561-569
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Tidskriftsartikel (refereegranskat)abstract
- Low-dimensional narrow band gap III-V compound semiconductors, such as InAs and InSb, have attracted much attention as one of promising platforms for studying Majorana zero modes and non-Abelian statistics relevant for topological quantum computation. So far, most of experimental studies were performed on hybrid devices based on one-dimensional semiconductor nanowires. In order to build complex topological circuits toward scalable quantum computing, exploring high-mobility two-dimensional (2D) III-V compound electron system with strong spin-orbit coupling is highly desirable. Here, we study quantum transport in high-mobility InSb nanosheet grown by molecular-beam epitaxy. The observations of Shubnikov-de Hass oscillations and quantum Hall states, together with the angular dependence of magnetotransport measurements, provide the evidence for the 2D nature of electronic states in InSb nanosheet. The presence of strong spin-orbit coupling in the InSb nanosheet is verified by the low-field magnetotransport measurements, characterized by weak antilocalization effect. Finally, we demonstrate the realization of high-quality InSb nanosheet-superconductor junctions with transparent interface. Our results not only advance the study of 2D quantum transport but also open up opportunities for developing hybrid topological devices based on 2D semiconducting nanosheets with strong spin-orbit coupling.
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| 4. |
- Wang, L. B., et al.
(författare)
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Phase-coherent transport and spin relaxation in InAs nanowires grown by molecule beam epitaxy
- 2015
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 106:17
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Tidskriftsartikel (refereegranskat)abstract
- We report low-temperature magnetotransport studies of individual InAs nanowires grown by molecule beam epitaxy. At low magnetic fields, the magnetoconductance characteristics exhibit a crossover between weak antilocalization and weak localization by changing either the gate voltage or the temperature. The observed crossover behavior can be well described in terms of relative scales of the transport characteristic lengths extracted based on the quasi-one-dimensional theory of weak localization in the presence of spin-orbit interaction. The spin relaxation length extracted from the magnetoconductance data is found to be in the range of 80-100 nm, indicating the presence of strong spin-orbit coupling in the InAs nanowires. Moreover, the amplitude of universal conductance fluctuations in the nanowires is found to be suppressed at low temperatures due to the presence of strong spin-orbit scattering. (C) 2015 AIP Publishing LLC.
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