The Experts below are selected from a list of 144 Experts worldwide ranked by ideXlab platform
Toyoko Arai - One of the best experts on this subject based on the ideXlab platform.
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Germanium Nanostructures on Silicon Observed by Scanning Probe Microscopy
MRS Bulletin, 2004Co-Authors: Masahiko Tomitori, Toyoko AraiAbstract:Scanning tunneling microscopy and noncontact atomic force microscopy have been used to observe germanium growth on Si(001) and Si(111). The atomically resolved images provide invaluable information on heteroepitaxial film growth from the viewpoints of both industrial application and basic science.We briefly review the history of characterizing heteroepitaxial Elemental Semiconductor systems by means of scanning probe microscopy (SPM), where the Stranski–Krastanov growth mode can be observed on the atomic scale: the detailed phase transition from layer-by-layer growth to three-dimensional cluster growth was elucidated by the use of SPM. In addition, we comment on the potential of SPM for examining the spectroscopic aspects of heteroepitaxial film growth, through the use of SPM tips with well-defined facets.
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Germaniumon Silicon Observed by Scanning Probe
2004Co-Authors: Masahiko Tomitori, Toyoko AraiAbstract:Abstract Scanning tunneling microscopy and noncontact atomic force microscopy have beenused to observe germanium growth on Si(001) and Si(111). The atomically resolvedimages provide invaluable information on heteroepitaxial film growth from the viewpointsof both industrial application and basic science. We briefly review the history ofcharacterizing heteroepitaxial Elemental Semiconductor systems by means of scanningprobe microscopy (SPM), where the Stranski–Krastanov growth mode can be observedon the atomic scale: the detailed phase transition from layer-by-layer growth to three-dimensional cluster growth was elucidated by the use of SPM. In addition, wecomment on the potential of SPM for examining the spectroscopic aspects ofheteroepitaxial film growth, through the use of SPM tips with well-defined facets. Keywords: AFM, atomic force microscopy, crystal growth, Elemental Semiconductors,germanium, nanostructures, scanning probe microscopy, scanning tunneling microscopy, silicon, SPM, STM.
Siebbeles L.d.a. - One of the best experts on this subject based on the ideXlab platform.
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Charge Mobility and Recombination Mechanisms in Tellurium van der Waals Solid
2019Co-Authors: Bhaskar P., Achtstein A.w., Vermeulen M.j.w., Siebbeles L.d.a.Abstract:Trigonal tellurium is a small band gap Elemental Semiconductor consisting of van der Waals bound one-dimensional helical chains of tellurium atoms. We study the temperature dependence of the charge carrier mobility and recombination pathways in bulk tellurium. Electrons and holes are generated by irradiation of the sample with 3 MeV electrons and detected by time-resolved microwave conductivity measurements. A theoretical model is used to explain the experimental observations for different charge densities and temperatures. Our analysis reveals a high room temperature mobility of 190 ± 20 cm2 V-1 s-1. The mobility is thermally deactivated, suggesting a band-like transport mechanism. According to our analysis, the charges predominantly recombine via radiative recombination with a radiative yield close to 98%, even at room temperature. The remaining charges recombine by either trap-assisted (Shockley-Read-Hall) recombination or undergo trapping to deep traps. The high mobility, near-unity radiative yield, and possibility of large-scale production of atomic wires by liquid exfoliation make Te of high potential for next-generation nanoelectronic and optoelectronic applications, including far-infrared detectors and lasers.
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Charge Mobility and Recombination Mechanisms in Tellurium van der Waals Solid
'American Chemical Society (ACS)', 2019Co-Authors: Bhaskar P., Achtstein A.w., Vermeulen M.j.w., Siebbeles L.d.a.Abstract:Trigonal tellurium is a small band gap Elemental Semiconductor consisting of van der Waals bound one-dimensional helical chains of tellurium atoms. We study the temperature dependence of the charge carrier mobility and recombination pathways in bulk tellurium. Electrons and holes are generated by irradiation of the sample with 3 MeV electrons and detected by time-resolved microwave conductivity measurements. A theoretical model is used to explain the experimental observations for different charge densities and temperatures. Our analysis reveals a high room temperature mobility of 190 ± 20 cm2 V-1 s-1. The mobility is thermally deactivated, suggesting a band-like transport mechanism. According to our analysis, the charges predominantly recombine via radiative recombination with a radiative yield close to 98%, even at room temperature. The remaining charges recombine by either trap-assisted (Shockley-Read-Hall) recombination or undergo trapping to deep traps. The high mobility, near-unity radiative yield, and possibility of large-scale production of atomic wires by liquid exfoliation make Te of high potential for next-generation nanoelectronic and optoelectronic applications, including far-infrared detectors and lasers.ChemE/Opto-electronic MaterialsChemE/O&O groe
Zhenyu Zhang - One of the best experts on this subject based on the ideXlab platform.
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magnetotransport signatures of weyl physics and discrete scale invariance in the Elemental Semiconductor tellurium
Proceedings of the National Academy of Sciences of the United States of America, 2020Co-Authors: Nan Zhang, Gan Zhao, P Wang, Lin Xie, Zhiyong Lin, Zhe Sun, Zhengfei Wang, Bin Cheng, Ming Yang, Zhenyu ZhangAbstract:The study of topological materials possessing nontrivial band structures enables exploitation of relativistic physics and development of a spectrum of intriguing physical phenomena. However, previous studies of Weyl physics have been limited exclusively to semimetals. Here, via systematic magnetotransport measurements, two representative topological transport signatures of Weyl physics, the negative longitudinal magnetoresistance and the planar Hall effect, are observed in the Elemental Semiconductor tellurium. More strikingly, logarithmically periodic oscillations in both the magnetoresistance and Hall data are revealed beyond the quantum limit and found to share similar characteristics with those observed in ZrTe5 and HfTe5. The log-periodic oscillations originate from the formation of two-body quasi-bound states formed between Weyl fermions and opposite charge centers, the energies of which constitute a geometric series that matches the general feature of discrete scale invariance (DSI). Our discovery reveals the topological nature of tellurium and further confirms the universality of DSI in topological materials. Moreover, introduction of Weyl physics into Semiconductors to develop “Weyl Semiconductors” provides an ideal platform for manipulating fundamental Weyl fermionic behaviors and for designing future topological devices.
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evidence for weyl fermions in the Elemental Semiconductor tellurium
arXiv: Materials Science, 2019Co-Authors: Nan Zhang, Gan Zhao, P Wang, Lin Xie, Zhiyong Lin, Zhe Sun, Zhengfei Wang, Zhenyu Zhang, Changgan ZengAbstract:The recent discovery of Weyl fermions in solids enables exploitation of relativistic physics and development of a spectrum of intriguing physical phenomena. They are constituted of pairs of Weyl points with two-fold band degeneracy, which in principle can be hosted in any materials without inversion or time-reversal symmetry. However, previous studies of Weyl fermions have been limited exclusively to semimetals. Here, by combining magneto-transport measurements, angle-resolved photoemission spectroscopy, and band structure calculations, Weyl fermions are identified in an Elemental Semiconductor tellurium. This is mainly achieved by direct observation of the representative transport signatures of the chiral anomaly, including the negative longitudinal magnetoresistance and the planar Hall effect. Semiconductor materials are well suited for band engineering, and therefore provide an ideal platform for manipulating the fundamental Weyl fermionic behaviors. Furthermore, introduction of Weyl physics into Semiconductors to develop "Weyl Semiconductors" also creates a new degree of freedom for the future design of Semiconductor electronic and optoelectronic devices.
Nan Zhang - One of the best experts on this subject based on the ideXlab platform.
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magnetotransport signatures of weyl physics and discrete scale invariance in the Elemental Semiconductor tellurium
Proceedings of the National Academy of Sciences of the United States of America, 2020Co-Authors: Nan Zhang, Gan Zhao, P Wang, Lin Xie, Zhiyong Lin, Zhe Sun, Zhengfei Wang, Bin Cheng, Ming Yang, Zhenyu ZhangAbstract:The study of topological materials possessing nontrivial band structures enables exploitation of relativistic physics and development of a spectrum of intriguing physical phenomena. However, previous studies of Weyl physics have been limited exclusively to semimetals. Here, via systematic magnetotransport measurements, two representative topological transport signatures of Weyl physics, the negative longitudinal magnetoresistance and the planar Hall effect, are observed in the Elemental Semiconductor tellurium. More strikingly, logarithmically periodic oscillations in both the magnetoresistance and Hall data are revealed beyond the quantum limit and found to share similar characteristics with those observed in ZrTe5 and HfTe5. The log-periodic oscillations originate from the formation of two-body quasi-bound states formed between Weyl fermions and opposite charge centers, the energies of which constitute a geometric series that matches the general feature of discrete scale invariance (DSI). Our discovery reveals the topological nature of tellurium and further confirms the universality of DSI in topological materials. Moreover, introduction of Weyl physics into Semiconductors to develop “Weyl Semiconductors” provides an ideal platform for manipulating fundamental Weyl fermionic behaviors and for designing future topological devices.
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evidence for weyl fermions in the Elemental Semiconductor tellurium
arXiv: Materials Science, 2019Co-Authors: Nan Zhang, Gan Zhao, P Wang, Lin Xie, Zhiyong Lin, Zhe Sun, Zhengfei Wang, Zhenyu Zhang, Changgan ZengAbstract:The recent discovery of Weyl fermions in solids enables exploitation of relativistic physics and development of a spectrum of intriguing physical phenomena. They are constituted of pairs of Weyl points with two-fold band degeneracy, which in principle can be hosted in any materials without inversion or time-reversal symmetry. However, previous studies of Weyl fermions have been limited exclusively to semimetals. Here, by combining magneto-transport measurements, angle-resolved photoemission spectroscopy, and band structure calculations, Weyl fermions are identified in an Elemental Semiconductor tellurium. This is mainly achieved by direct observation of the representative transport signatures of the chiral anomaly, including the negative longitudinal magnetoresistance and the planar Hall effect. Semiconductor materials are well suited for band engineering, and therefore provide an ideal platform for manipulating the fundamental Weyl fermionic behaviors. Furthermore, introduction of Weyl physics into Semiconductors to develop "Weyl Semiconductors" also creates a new degree of freedom for the future design of Semiconductor electronic and optoelectronic devices.
Masahiko Tomitori - One of the best experts on this subject based on the ideXlab platform.
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Germanium Nanostructures on Silicon Observed by Scanning Probe Microscopy
MRS Bulletin, 2004Co-Authors: Masahiko Tomitori, Toyoko AraiAbstract:Scanning tunneling microscopy and noncontact atomic force microscopy have been used to observe germanium growth on Si(001) and Si(111). The atomically resolved images provide invaluable information on heteroepitaxial film growth from the viewpoints of both industrial application and basic science.We briefly review the history of characterizing heteroepitaxial Elemental Semiconductor systems by means of scanning probe microscopy (SPM), where the Stranski–Krastanov growth mode can be observed on the atomic scale: the detailed phase transition from layer-by-layer growth to three-dimensional cluster growth was elucidated by the use of SPM. In addition, we comment on the potential of SPM for examining the spectroscopic aspects of heteroepitaxial film growth, through the use of SPM tips with well-defined facets.
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Germaniumon Silicon Observed by Scanning Probe
2004Co-Authors: Masahiko Tomitori, Toyoko AraiAbstract:Abstract Scanning tunneling microscopy and noncontact atomic force microscopy have beenused to observe germanium growth on Si(001) and Si(111). The atomically resolvedimages provide invaluable information on heteroepitaxial film growth from the viewpointsof both industrial application and basic science. We briefly review the history ofcharacterizing heteroepitaxial Elemental Semiconductor systems by means of scanningprobe microscopy (SPM), where the Stranski–Krastanov growth mode can be observedon the atomic scale: the detailed phase transition from layer-by-layer growth to three-dimensional cluster growth was elucidated by the use of SPM. In addition, wecomment on the potential of SPM for examining the spectroscopic aspects ofheteroepitaxial film growth, through the use of SPM tips with well-defined facets. Keywords: AFM, atomic force microscopy, crystal growth, Elemental Semiconductors,germanium, nanostructures, scanning probe microscopy, scanning tunneling microscopy, silicon, SPM, STM.