Negative differential resistance in “sulflower”-based molecular junction predicted by first-principles study

Author(s):  
Ji-Mei Shen ◽  
Jing Liu

The electronic transport behavior of a sulflower molecule sandwiched between metal leads by S atom connecting apex Au or Ag atoms was investigated using a first-principles study by current-voltage characteristics, transmission spectrum and local density of states. Negative differential resistance (NDR) effect which originates from Coulomb blockade driven by bias was obtained. We also found that the differential conductance can be modulated by the metal leads with different work functions, which promise the potential applications in molecular devices in the future.

Author(s):  
С.О. Слипченко ◽  
А.А. Подоскин ◽  
О.С. Соболева ◽  
В.С. Юферев ◽  
В.С. Головин ◽  
...  

AbstractThe current–voltage characteristics of n ^+-GaAs/ n ^0-GaAs/ N ^0-AlGaAs/ N ^+-AlGaAs/ n ^+-GaAs isotype heterostructures and n ^+-GaAs/ n ^0-GaAs/ n ^+-GaAs homostructures are studied. It is shown that, for a heterostructure under reverse bias providing the injection of electrons from n ^0-GaAs into N ^0-AlGaAs, the maximum operating voltage reaches a value of 48 V at a thickness of the N ^0-AlGaAs layer of 1 . 0 μm, and the current–voltage characteristic has no region of negative differential resistance. The operation of a homostructure is accompanied by a transition to the negative-differential-resistance region at a voltage of 10 V. Theoretical analysis in terms of the energy-balance model demonstrated that the reverse-biased isotype heterostructure has no negative-differential-resistance region because, in this case, the field domain does not collapse in contrast to what occurs in homostructures.


2021 ◽  
Author(s):  
Denice Feria ◽  
Sonia Sharma ◽  
Yu-Ting Chen ◽  
Zhi-Ying Weng ◽  
Kuo-Pin Chiu ◽  
...  

Abstract Understanding the mechanism of the negative differential resistance (NDR) in transition metal dichalcogenides is essential for fundamental science and the development of electronic devices. Here, the NDR of the current-voltage characteristics was observed based on the glutamine-functionalized WS2 quantum dots (QDs). The NDR effect can be adjusted by varying the applied voltage range, air pressure, surrounding gases, and relative humidity. A peak-to-valley current ratio as high as 6.3 has been achieved at room temperature. Carrier trapping induced by water molecules was suggested to be responsible for the mechanism of the NDR in the glutamine-functionalized WS2 QDs. Investigating the NDR of WS2 QDs may promote the development of memory applications and emerging devices.


2021 ◽  
Vol 67 ◽  
pp. 25-31
Author(s):  
Sophia R. Figarova ◽  
Elvin M. Aliyev ◽  
Rashad G. Abaszade ◽  
R.I. Alekberov ◽  
Vagif R. Figarov

Graphene oxide/sulphur compound was synthesized by Hammers method. The chemical composition, presence/quantity of functional groups, exfoliation level, number of layers, crystallite size of graphene oxide/sulphur were characterized by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy images. The current-voltage characteristics of the samples were measured in air at room temperature. In the I - V characteristic curve of graphene oxide/sulphur compound with the ratio of oxygen to carbon of 3.54 and that to sulphur of 42.54, negative differential resistance was observed. The negative differential resistance is attributed to current carrier transitions between the localized states formed by functional groups.


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