scholarly journals Van der Waals metal-semiconductor junction: Weak Fermi level pinning enables effective tuning of Schottky barrier

2016 ◽  
Vol 2 (4) ◽  
pp. e1600069 ◽  
Author(s):  
Yuanyue Liu ◽  
Paul Stradins ◽  
Su-Huai Wei

Two-dimensional (2D) semiconductors have shown great potential for electronic and optoelectronic applications. However, their development is limited by a large Schottky barrier (SB) at the metal-semiconductor junction (MSJ), which is difficult to tune by using conventional metals because of the effect of strong Fermi level pinning (FLP). We show that this problem can be overcome by using 2D metals, which are bounded with 2D semiconductors through van der Waals (vdW) interactions. This success relies on a weak FLP at the vdW MSJ, which is attributed to the suppression of metal-induced gap states. Consequently, the SB becomes tunable and can vanish with proper 2D metals (for example, H-NbS2). This work not only offers new insights into the fundamental properties of heterojunctions but also uncovers the great potential of 2D metals for device applications.

1992 ◽  
Vol 281 ◽  
Author(s):  
A. D. Marwick ◽  
M. O. Aboelfotoh ◽  
R. Casparis

ABSTRACTIt is shown that the presence of 8 × 1015 hydrogen atoms/cm2 in the CoSi2/Si (100) interface causes an increase in the Schottky barrier height of 120 meV, and that passivation of dopants in the substrate is not the cause of this change. The data is evidence that the position of the Fermi level in this interface is controlled by defect-related interface states. After hydrogenation the Schottky barrier height agrees with that predicted by theory for Fermi level pinning by virtual gap states of the silicon.


2021 ◽  
pp. 2001212
Author(s):  
Tien Dat Ngo ◽  
Zheng Yang ◽  
Myeongjin Lee ◽  
Fida Ali ◽  
Inyong Moon ◽  
...  

Author(s):  
Tien Dat Ngo ◽  
Min Sup Choi ◽  
Myeongjin Lee ◽  
Fida Ali ◽  
Won Jong Yoo

A technique to form the edge contact in two-dimensional (2D) based field-effect transistors (FETs) has been intensively studied for the purpose of achieving high mobility and also recently overcoming the...


2020 ◽  
Vol 8 (9) ◽  
pp. 3113-3119 ◽  
Author(s):  
Qian Wang ◽  
Yangfan Shao ◽  
Penglai Gong ◽  
Xingqiang Shi

Thickness-dependent performance of metal–two-dimensional semiconductor junctions in electronics/optoelectronics have attracted increasing attention but, currently, little knowledge about the micro-mechanism of this thickness dependence is available.


Nanoscale ◽  
2020 ◽  
Vol 12 (16) ◽  
pp. 8883-8889 ◽  
Author(s):  
Ronen Dagan ◽  
Yonatan Vaknin ◽  
Yossi Rosenwaks

Gap states and Fermi level pinning play an important role in all semiconductor devices, but even more in transition metal dichalcogenide-based devices due to their high surface to volume ratio and the absence of intralayer dangling bonds.


2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Yi-Hsun Chen ◽  
Chih-Yi Cheng ◽  
Shao-Yu Chen ◽  
Jan Sebastian Dominic Rodriguez ◽  
Han-Ting Liao ◽  
...  

AbstractIn two-dimensional (2D)-semiconductor-based field-effect transistors and optoelectronic devices, metal–semiconductor junctions are one of the crucial factors determining device performance. The Fermi-level (FL) pinning effect, which commonly caused by interfacial gap states, severely limits the tunability of junction characteristics, including barrier height and contact resistance. A tunneling contact scheme has been suggested to address the FL pinning issue in metal–2D-semiconductor junctions, whereas the experimental realization is still elusive. Here, we show that an oxidized-monolayer-enabled tunneling barrier can realize a pronounced FL depinning in indium selenide (InSe) transistors, exhibiting a large pinning factor of 0.5 and a highly modulated Schottky barrier height. The FL depinning can be attributed to the suppression of metal- and disorder-induced gap states as a result of the high-quality tunneling contacts. Structural characterizations indicate uniform and atomically thin-surface oxidation layer inherent from nature of van der Waals materials and atomically sharp oxide–2D-semiconductor interfaces. Moreover, by effectively lowering the Schottky barrier height, we achieve an electron mobility of 2160 cm2/Vs and a contact barrier of 65 meV in two-terminal InSe transistors. The realization of strong FL depinning in high-mobility InSe transistors with the oxidized-monolayer presents a viable strategy to exploit layered semiconductors in contact engineering for advanced electronics and optoelectronics.


2019 ◽  
Vol 9 (23) ◽  
pp. 5014
Author(s):  
Courtin ◽  
Moréac ◽  
Delhaye ◽  
Lépine ◽  
Tricot ◽  
...  

Fermi level pinning at metal/semiconductor interfaces forbids a total control over the Schottky barrier height. 2D materials may be an interesting route to circumvent this problem. As they weakly interact with their substrate through Van der Waals forces, deposition of 2D materials avoids the formation of the large density of state at the semiconductor interface often responsible for Fermi level pinning. Here, we demonstrate the possibility to alleviate Fermi-level pinning and reduce the Schottky barrier height by the association of surface passivation of germanium with the deposition of 2D graphene.


1999 ◽  
Vol 86 (12) ◽  
pp. 6890-6894 ◽  
Author(s):  
M. Mamor ◽  
O. Nur ◽  
M. Karlsteen ◽  
M. Willander ◽  
F. D. Auret

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