Insertion of an ultrathin Al2 O3 interfacial layer for Schottky barrier height reduction in WS2 field-effect transistors

Nanoscale
Shan ZhengJohn Robertson

Abstract

We report an effective approach for reducing the Schottky barrier height (SBH) in the source and drain (S/D) contacts of WS2 field-effect transistors (FETs) using an ultrathin Al2O3 interfacial layer between the metal and WS2. Al2O3 with various thicknesses was deposited to study the effect of the insulator thickness on contact resistances. The reduction of the SBH by inserting an ultrathin insulator was confirmed via both calculations and experiments, while further increasing the thickness of the insulator introduces a tunneling barrier that leads to the decrease in the current. By analyzing the metal/WS2 contact using four different metals, the density of gap states caused by defects at the interface is found to be the main reason for the Fermi level pinning, and this metal-insulator-semiconductor (MIS) contact structure shows its great advantage in the Fermi level depinning, a large improvement of the on-current, and enhanced field-effect mobilities in WS2 FETs due to an Al2O3 capping layer. This work demonstrates that the SBH can be effectively modulated by the optimization of the inserted interfacial material and its thickness.

References

May 16, 2009·Journal of Computational Chemistry·B R BrooksM Karplus
Feb 1, 2011·Nature Nanotechnology·B RadisavljevicA Kis
Nov 8, 2012·Nature Nanotechnology·Qing Hua WangMichael S Strano
Dec 18, 2012·Nano Letters·Saptarshi DasJoerg Appenzeller
Oct 3, 2013·Nano Letters·Andres Castellanos-GomezGary A Steele
Feb 4, 2014·ACS Nano·Stephen McDonnellChristopher L Hinkle
Jul 30, 2014·ACS Nano·Dmitry OvchinnikovAndras Kis
Oct 14, 2014·Nano Letters·Lingming YangPeide D Ye
Nov 28, 2014·Nanoscale·Muhammad Waqas IqbalJonghwa Eom
Jan 28, 2015·Nano Letters·Matthew J HollanderSuman Datta
Nov 3, 2015·ACS Applied Materials & Interfaces·Yuzheng GuoJohn Robertson
Dec 15, 2015·Scientific Reports·Tamie A J LohAndrew T S Wee
Jul 30, 2016·Science·K S NovoselovA H Castro Neto
Dec 20, 2017·Nature Nanotechnology·Mengwei SiPeide D Ye

❮ Previous
Next ❯

Citations

Feb 6, 2021·ACS Applied Materials & Interfaces·Jinho LimSeunghyun Lee
Mar 12, 2021·The Journal of Physical Chemistry Letters·Hui YangXiaosheng Fang
Jan 1, 2020·ACS Applied Materials & Interfaces·Jisu JangSun Jin Yun
Aug 21, 2019·ACS Applied Materials & Interfaces·Seung-Hwan KimHyun-Yong Yu

❮ Previous
Next ❯

Methods Mentioned

BETA
optical microscopy
transmission electron microscopy
Optical
X-ray

Software Mentioned

CASTEP

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.