Ultrathin undoped tetrahedral amorphous carbon films: thickness dependence of the electronic structure and implications for their electrochemical behaviour

Physical Chemistry Chemical Physics : PCCP
V S ProtopopovaJ Koskinen

Abstract

In this paper we show that the electronic properties of ultrathin tetrahedral amorphous carbon (ta-C) films are heavily dependent on their thickness. By using scanning tunnelling spectroscopy, Raman spectroscopy, and conductive atomic force microscopy, it was found that a decrease of ta-C thickness from 30 to 7 nm leads to (i) the narrowing of the band gap; (ii) appearance of shallower monoenergetic traps as well as the increase of their concentration; (iii) the increase of the equilibrium concentration of free charge carriers and their mobility; which were caused by (iv) the increase in the sp(2) fraction. However, beyond a certain ta-C thickness (7 nm) the electronic properties of the studied samples start to deteriorate, which is highly likely related to titanium oxide formation at the Ti/ta-C interface. The same tendency is observed for the sample with beforehand air-formed native titanium oxide at the interface. With respect to the last point, it is suggested that the ta-C layer has no uniform coverage if its thickness is small enough (less than 7 nm). The experimental results were rationalized by detailed atomistic simulations. By using the so-called "Tauc plot" we introduce the possibility of the coexistence of bulk and ...Continue Reading

References

Jan 18, 1967·Journal of the American Chemical Society·M D HawleyR N Adams
Dec 15, 1994·Physical Review. B, Condensed Matter·P E Blöchl
Oct 15, 1996·Physical Review. B, Condensed Matter·G Kresse, J Furthmüller
Jun 4, 1990·Physical Review Letters·S AljishiL Ley
Oct 28, 1996·Physical Review Letters·J P PerdewM Ernzerhof
Oct 16, 2004·Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences·Andrea Carlo Ferrari, John Robertson
Jun 19, 2008·Chemical Reviews·Richard L McCreery
Feb 10, 2011·Pharmacological Reviews·Jean-Martin Beaulieu, Raul R Gainetdinov
Feb 22, 2011·ACS Nano·Wan LiDaniel C Ralph
Aug 7, 2013·Applied Physics Letters·Prabhu U ArumugamPaul A Garris
Nov 26, 2013·Materials Science & Engineering. C, Materials for Biological Applications·Tomi LaurilaJari Koskinen
Dec 7, 2013·Analytical Chemistry·Anisha N PatelPatrick R Unwin

❮ Previous
Next ❯

Citations

Nov 22, 2007·Pharmacological Research : the Official Journal of the Italian Pharmacological Society·D GiannessiS Del Ry
Jun 3, 2017·ACS Applied Materials & Interfaces·Jong-Chul YoonJi-Hyun Jang
Oct 21, 2020·Scientific Reports·Anastasia LudwigClaudio Rivera

❮ Previous
Next ❯

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.