Step edge influence on barrier height and contact area in vertical heterojunctions between epitaxial graphene and n-type 4H-SiC

2014 ◽  
Vol 104 (7) ◽  
pp. 073508 ◽  
Author(s):  
M. J. Tadjer ◽  
T. J. Anderson ◽  
R. L. Myers-Ward ◽  
V. D. Wheeler ◽  
L. O. Nyakiti ◽  
...  
Keyword(s):  
Barrier Height ◽  
Contact Area ◽  
Epitaxial Graphene ◽  
Step Edge ◽  
Edge Influence

Inhomogeneous ohmic contacts: Barrier height and contact area determination

2012 ◽  
Vol 101 (5) ◽  
pp. 051604 ◽  
Author(s):  
Yang Li ◽  
Wei Long ◽  
Raymond T. Tung
Keyword(s):  
Barrier Height ◽  
Contact Area ◽  
Ohmic Contacts ◽  
Area Determination

Electrical Nanocharacterization of Epitaxial Graphene/Silicon Carbide Schottky Contacts

2014 ◽  
Vol 778-780 ◽  
pp. 1142-1145 ◽  
Author(s):  
Filippo Giannazzo ◽  
Stefan Hertel ◽  
Andreas Albert ◽  
Antonino La Magna ◽  
Fabrizio Roccaforte ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Schottky Barrier ◽  
Barrier Height ◽  
Photoelectron Spectroscopy ◽  
Schottky Contact ◽  
Epitaxial Graphene ◽  
Schottky Contacts ◽  
Specific Contact Resistance ◽  
Monolayer Graphene ◽  
Conductive Atomic Force Microscopy

Epitaxial graphene fabricated by thermal decomposition of the Si-face of silicon carbide (SiC) forms a defined interface to the SiC substrate. As-grown monolayer graphene with buffer layer establishes an ohmic interface even to low-doped (e. g. [N] ≈ 1015 cm-3) SiC, and a specific contact resistance as low as ρC = 5.9×10-6 Ωcm2 can be achieved on highly n-doped SiC layers. After hydrogen intercalation of monolayer graphene, the so-called quasi-freestanding graphene forms a Schottky contact to n-type SiC with a Schottky barrier height of 1.5 eV as determined from C-V analysis and core level photoelectron spectroscopy (XPS). This value, however, strongly deviates from the respective value of less than 1 eV determined from I-V measurements. It was found from conductive atomic force microscopy (C-AFM) that the Schottky barrier is locally lowered on other crystal facets located at substrate step edges. For very small Schottky contacts, the barrier height extracted from I-V curves approaches the value of 1.5 eV from C-V and XPS.

Nanomechanical Effects

2021 ◽  
pp. 253-272
Author(s):  
C. Julian Chen
Keyword(s):  
Barrier Height ◽  
Contact Area ◽  
Soft Materials ◽  
Sample Surface ◽  
Soft Material ◽  
Measurable Effect ◽  
Tunneling Barrier ◽  
Hard Materials ◽  
Small Force ◽  
The Stability

This chapter discusses the effect of force and deformation of the tip apex and the sample surface in the operation and imaging mechanism of STM and AFM. Because the contact area is of atomic dimension, a very small force and deformation would generate a large measurable effect. Three effects are discussed. First is the stability of the STM junction, which depends on the rigidity of the material. For soft materials, hysterisis is more likely. For rigid materials, the approaching and retraction cycles are continuous and reproducible. Second is the effect of force and deformation to the STM imaging mechanism. For soft material such as graphite, force and deformation can amplify the observed corrugation. For hard materials as most metals, force and deformation can decrease the observed corrugation. Finally, the effect of force and deformation on tunneling barrier height measurements is discussed.

Atomistic simulations of contact area and conductance at nanoscale interfaces

Nanoscale ◽  
2017 ◽  
Vol 9 (43) ◽  
pp. 16852-16857 ◽  
Author(s):  
Xiaoli Hu ◽  
Ashlie Martini
Keyword(s):  
Contact Area ◽  
Graphite Surface ◽  
Step Edge ◽  
Atomistic Simulations ◽  
Nanoscale Interfaces ◽  
Gold Probe

Atomistic simulations were used to study conductance across the interface between a nanoscale gold probe and a graphite surface with a step edge.

scholarly journals Туннельный ток во встречных диодах Шоттки, образованных контактами между вырожденным GaN n-типа и металлом

2018 ◽  
Vol 52 (6) ◽  
pp. 630
Author(s):  
И.О. Майборода ◽  
Ю.В. Грищенко ◽  
И.С. Езубченко ◽  
И.С. Соколов ◽  
И.А. Черных ◽  
...  
Keyword(s):  
Barrier Height ◽  
Potential Barrier ◽  
Current Density ◽  
Contact Area ◽  
Electron Tunneling ◽  
Schottky Diodes ◽  
Nonlinear Behavior ◽  
Free Carrier ◽  
Potential Barrier Height ◽  
Potential Barriers

AbstractThe nonlinear behavior of the I – V characteristics of symmetric contacts between a metal and degenerate n -GaN, which form oppositely connected Schottky diodes, is investigated at free-carrier densities from 1.5 × 10^19 to 2.0 × 10^20 cm^–3 in GaN. It is demonstrated that, at an electron density of 2.0 × 10^20 cm^–3, the conductivity between metal (chromium) and GaN is implemented via electron tunneling and the resistivity of the Cr–GaN contact is 0.05 Ω mm. A method for determining the parameters of potential barriers from the I – V characteristics of symmetric opposite contacts is developed. The effect of pronounced nonuniformity of the current density and voltage distributions over the contact area at low contact resistivity is taken into account. The potential-barrier height for Cr– n ^+-GaN contacts is found to be 0.47 ± 0.04 eV.

On the Viability of Au/3C-SiC Schottky Barrier Diodes

2010 ◽  
Vol 645-648 ◽  
pp. 677-680 ◽  
Author(s):  
Jens Eriksson ◽  
Ming Hung Weng ◽  
Fabrizio Roccaforte ◽  
Filippo Giannazzo ◽  
Salvatore di Franco ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Schottky Barrier ◽  
Barrier Height ◽  
Uv Irradiation ◽  
Contact Area ◽  
Schottky Diodes ◽  
Crystal Defects ◽  
Semiconductor Surface ◽  
Conductive Atomic Force Microscopy ◽  
Transmission Electron

The electrical characteristics of Au/3C-SiC Schottky diodes were studied and related to crystal defects. A structural analysis performed by transmission electron microscopy (TEM), combined with a current mapping of the surface by conductive atomic force microscopy (C-AFM), indicated that stacking faults (SFs) are the conductive defects having the biggest influence on the electrical properties of the Schottky barrier on 3C-SiC. Further, C-AFM current mapping of the semiconductor surface also showed that an ultraviolet (UV) irradiation process enables the electrical passivation of the SFs, due to their preferential oxidation. From current-voltage (I-V) measurements in diodes of different area (different amount of defects) it was observed that, for the non-irradiated surface, no significant dependence of the Schottky barrier height (ΦB) on the contact area could be observed. On contrast, after the UV-irradiation, ΦB gradually increases with decreasing contact area, ultimately leading to a nearly ideal value of the barrier height for the smallest diodes. The results indicate that even after the passivation of SFs there are still some electrically active defects contributing to deleterious conduction, responsible for a worsening of the electrical properties of the diodes.

Load-Bearing in the Ovine Medial Tibial Condyle: Effect of Meniscectomy

1993 ◽  
Vol 06 (02) ◽  
pp. 100-104 ◽  
Author(s):  
D. M. Pickles ◽  
C. R. Bellenger
Keyword(s):  
Knee Joint ◽  
Contact Area ◽  
Mammalian Species ◽  
Total Removal ◽  
Load Bearing ◽  
Human Knee ◽  
Biochemical Effects ◽  
Pressure Sensitive ◽  
Medial Meniscectomy ◽  
Tibial Condyle

SummaryTotal removal of a knee joint meniscus is followed by osteoarthritis in many mammalian species. Altered load-bearing has been observed in the human knee following meniscectomy but less is known about biochemical effects of meniscectomy in other species. Using pressure sensitive paper in sheep knee (stifle) joints it was found that, for comparable loads, the load-bearing area on the medial tibial condyle was significantly reduced following medial meniscectomy. Also, for loads of between 50 N and 500 N applied to the whole joint, the slope of the regression of contact area against load was much smaller. Following medial meniscectomy, the ability to increase contact area as load increased was markedly reduced.The load bearing area on the medial tibial condyle was reduced following meniscectomy.

High Quality HfO2 Film and Its Applications in Novel Poly-Si Devices

2002 ◽  
Vol 716 ◽  
Author(s):  
K.L. Ng ◽  
N. Zhan ◽  
M.C. Poon ◽  
C.W. Kok ◽  
M. Chan ◽  
...  
Keyword(s):  
Barrier Height ◽  
Nonvolatile Memory ◽  
Dielectric Material ◽  
Tunneling Current ◽  
Interface Layer ◽  
Si Substrate ◽  
Hfo2 Film ◽  
Effective Barrier Height ◽  
Effective Barrier ◽  
Nonvolatile Memory Devices

AbstractHfO2 as a dielectric material in MOS capacitor by direct sputtering of Hf in an O2 ambient onto a Si substrate was studied. The results showed that the interface layer formed between HfO2 and the Si substrate was affected by the RTA time in the 500°C annealing temperature. Since the interface layer is mainly composed of hafnium silicate, and has high interface trap density, the effective barrier height is therefore lowered with increased RTA time. The change in the effective barrier height will affect the FN tunneling current and the operation of the MOS devices when it is applied for nonvolatile memory devices.

Fabrication of Step-Edge Vertical-Channel Organic Transistors by Selective Electro-Spray Deposition

2015 ◽  
Vol E98.C (2) ◽  
pp. 80-85
Author(s):  
Hiroshi YAMAUCHI ◽  
Shigekazu KUNIYOSHI ◽  
Masatoshi SAKAI ◽  
Kazuhiro KUDO
Keyword(s):  
Spray Deposition ◽  
Vertical Channel ◽  
Step Edge ◽  
Organic Transistors
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