Charge transport spectra in superconductor-InAs/GaSb-superconductor heterostructures

2021 ◽  
Author(s):  
Kuei Sun ◽  
Zhi-qiang Bao ◽  
Wenlong Yu ◽  
Samuel D Hawkins ◽  
John F Klem ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Quantum Well ◽  
Charge Transport ◽  
Gate Voltage ◽  
Differential Resistance ◽  
Charge Carrier Density ◽  
Quasi Particle ◽  
Current Voltage ◽  
Current Voltage Relation

Abstract Charge transport physics in InAs/GaSb bi-layer systems has recently attracted attention for the experimental search for two-dimensional topological superconducting states in solids. Here we report measurement of charge transport spectra of nano devices consisting of an InAs/GaSb quantum well sandwiched by tantalum superconductors. We explore the current-voltage relation as a function of the charge-carrier density in the quantum well controlled by a gate voltage and an external magnetic field. We observe three types of differential resistance peaks, all of which can be effectively tuned by the external magnetic field, and, however, two of which appear at electric currents independent of the gate voltage, indicating a dominant mechanism from the superconductor and the system geometry. By analyzing the spectroscopic features, we nd that the three types of peaks identify Andreev reflections, quasi-particle interference, and superconducting transitions in the device, respectively. Our results provide a basis for further exploration of possible topological superconducting state in the InAs/GaSb system.

CHARGE TRANSPORT THROUGH CARBON NANOTUBE OR FULLERENE–MOLECULE–SILICON JUNCTIONS

NANO ◽  
2007 ◽  
Vol 02 (05) ◽  
pp. 285-294
Author(s):  
FU-REN F. FAN ◽  
BO CHEN ◽  
AUSTEN K. FLATT ◽  
JAMES M. TOUR ◽  
ALLEN J. BARD
Keyword(s):  
Carbon Nanotube ◽  
Charge Transport ◽  
Electron Acceptor ◽  
Negative Differential Resistance ◽  
Fullerene Molecule ◽  
Differential Resistance ◽  
Electron Donors ◽  
Switching Behavior ◽  
Current Voltage ◽  
Bistable Switching

We report here the current–voltage (i–V) characteristics of several (n++- Si /MNOPE/ C 60/ Pt -tip) or (n++- Si /MNOPE/SWCNT/ Pt -tip) junctions, where MNOPE = 2'-mononitro-4, 4'-bis(phenylethynyl)-1-phenylenediazonium and SWCNT = single wall carbon nanotube. A layer of C 60 or SWCNT-derivatized MNOPE has strong effect on the i–V behavior of the junctions, including rectification, negative differential resistance (NDR) and switching behaviors. The i–V curve of a grafted molecular monolayer (GMM) of MNOPE atop n++- Si shows NDR behavior, whereas those of C 60- and SWCNT-derivatized GMMs of MNOPE on n++- Si show strong rectifying behavior with opposite rectification polarities. With C 60, larger currents were found with negative tip bias, while with SWCNT, the forward top bias was positive. Because C 60 tends to be a good electron acceptor and SWCNTs tend to be good electron donors, they show different i–V behavior, as observed. Some of the (n++- Si /MNOPE/SWCNT/ Pt -tip) junctions also show reversible bistable switching behavior.

SPACE-CHARGE EFFECT IN UNINTENTIONALLY N-DOPED SILICON

2012 ◽  
Vol 26 (08) ◽  
pp. 1250048 ◽  
Author(s):  
KANKAN CONG ◽  
YANG JI
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Space Charge ◽  
Space Charge Effect ◽  
Charge Effect ◽  
Temperature Range ◽  
Ohmic Behavior ◽  
Current Voltage ◽  
Doped Silicon ◽  
High Bias

We report experimental results on current–voltage characteristics of Au-Ti/n-Si/Au-Ti devices made on unintentionally n-doped silicon, which depend dramatically on temperature and external magnetic field. While such devices show Ohmic behavior in the temperature range 154–300 K, space-charge effect dominates at high bias voltages in the temperature range 77–154 K. In the later case, external magnetic field may increase its breakdown voltage, thus inducing large positive magnetoresistance similar to those reported by other groups.

Effects of Magnetic Fields on PN Junctions in Piezomagnetic–Piezoelectric Semiconductor Composite Fibers

2020 ◽  
Vol 12 (08) ◽  
pp. 2050085
Author(s):  
Chao Liang ◽  
Chunli Zhang ◽  
Weiqiu Chen ◽  
Jiashi Yang
Keyword(s):  
Magnetic Field ◽  
Composite Fiber ◽  
Transverse Magnetic ◽  
Piezoelectric Semiconductor ◽  
One Dimensional ◽  
Current Voltage ◽  
Potential Applications ◽  
Multiferroic Composite ◽  
The Magnetic Field ◽  
Current Voltage Relation

We study the electromechanical and electrical behaviors of a PN junction in a multiferroic composite fiber, consisting of a piezoelectric semiconductor (PS) layer between two piezomagnetic (PM) layers, under a transverse magnetic field. Based on the derived one-dimensional model for multiferroic composite semiconductor structures, we obtain the linear analytical solution for the built-in potential and electric field in the junction when there is no applied voltage between the two ends of the fiber. When a bias voltage is applied over the two ends of the fiber, a nonlinear numerical analysis is performed for the current–voltage relation. Both a homogeneous junction with a uniform PS layer and a heterogeneous junction with two different PSs on different sides of the junctions are studied. It is found that overall the homogeneous junction is essentially unaffected by the magnetic field, and the heterojunction is sensitive to the magnetic field with potential applications in piezotronics.

Band-Tailored InAs/GaSb Superlattice in Infrared Application

2013 ◽  
Vol 750-752 ◽  
pp. 936-940
Author(s):  
Jie Guo ◽  
Rui Ting Hao ◽  
Qian Run Zhao ◽  
Shi Qing Man
Keyword(s):  
Band Structure ◽  
Lattice Mismatch ◽  
Differential Resistance ◽  
Energy Band Structure ◽  
Cutoff Wavelength ◽  
Gasb Layer ◽  
Interface Control ◽  
Infrared Photodiode ◽  
Current Voltage ◽  
Current Voltage Relation

The energy band structure of InAs/GaSb superlattice can be tailored by changing the thickness of InAs or GaSb layer thickness. Different superlattice as InAs/GaSb (4ML/8ML, 8ML/8ML and 16ML/7ML) for cut-off wavelengths from short to long IR wavelength were designed and deposited on GaSb substrates by melocular beam epitaxy system. The lattice mismatch was below 1000ppm under the careful Ga1-xInx- type interface control. The responsitivity revealed the band structure in InAs/GaSb superlattice can be tailored and the cutoff wavelength was from 2.5μm to 11μm. The current-voltage relation and the differential resistance in infrared photodiode were also measured and studied.

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