The Interplay of Nanocontact and Electrical Properties of ZnO and InP Nanowires and Polyaniline Nanofibers

2009 ◽  
Vol 1198 ◽  
Author(s):  
Yen-Fu Lin ◽  
Wen-Bin Jian
Keyword(s):  
Electron Beam ◽  
Electrical Properties ◽  
Contact Resistance ◽  
Ohmic Contacts ◽  
Electrical Contact ◽  
Schottky Contacts ◽  
Specific Contact Resistance ◽  
Electrical Contact Resistance ◽  
Polyaniline Nanofibers ◽  
Current Voltage

AbstractThe interface problems in nanomaterial based electronics play important roles. We have learned that the nanocontact, due to its reduced contact area, could give a high electrical contact resistance and a nonlinear current-voltage behavior though the specific contact resistance is in the same order of magnitude as that of macroscopic contacts. Through the current-voltage and temperature behaviors, the nanocontact properties could be categorized into Ohmic and Schottky types. The electrical properties of the nanowire based two-probe devices could be rationalized as two Ohmic contacts, one Ohmic and one Schottky contacts, and two back-to-back Schottky contacts. Moreover, the nanocontact could be treated as a one-dimensional disordered electron system for further studies. After the intrinsic nanowire and contact resistances are separated from each other, the electron transport and the carrier concentration of native doping in ZnO and InP nanowires can be determined. The nanowires are determined to have low carrier concentrations, implying a high sensitivity to light and gas. The contact and nanowire dominated two-probe devices are exposed to light and gas to identify the contact effects. In addition to the inorganic nanowires, the organic nanomaterials, the HCl-doped polyaniline nanofibers, can be analyzed by using the same approach. The dielectrophoresis technique is implemented to position nanofibers into an electron-beam lithographically patterned nanogap. To shine the electron-beam on contact areas, the organic/inorganic nanocontact resistance is reduced so as to probe the intrinsic electrical property of a single polyaniline nanofiber.

scholarly journals Comparison of Electrical Properties of Ohmic Contact Realized on p-Type 4H-SiC

2008 ◽  
Vol 600-603 ◽  
pp. 639-642
Author(s):  
Duy Minh Nguyen ◽  
Christophe Raynaud ◽  
Mihai Lazar ◽  
Heu Vang ◽  
Dominique Planson
Keyword(s):  
Surface Roughness ◽  
Electrical Properties ◽  
Contact Resistance ◽  
Carrier Mobility ◽  
Ohmic Contacts ◽  
Series Resistance ◽  
Specific Contact Resistance ◽  
Specific Contact ◽  
P Type ◽  
Post Implantation

N+ 4H-SiC commercial substrates with n-type epilayers have been used to realize bipolar diodes and TLM structures. The p-type emitter of diodes was realized by Al implantations followed by a post-implantation annealing with or without a graphite capping layer. Ohmic contacts were formed by depositing Ti/Ni on the backside and Ni/Al on the topside of the wafer. It appears that capping the sample during the annealing reduces considerably the surface roughness and the specific contact resistance. Sheet resistance and specific contact resistance as low as 2kΩ/□ and respectively 1.75×10-4 Ωcm² at 300 K have been obtained. I-V measurements as a function of temperature have been performed from ~100 to ~500 K. The variations of the series resistance vs. temperature can be explained by the freeze-out of carriers and by the variation of carrier mobility.

scholarly journals Методики исследования электрического контактного сопротивления в структуре металлическая пленка--полупроводник

2022 ◽  
Vol 56 (1) ◽  
pp. 31
Author(s):  
М.Ю. Штерн ◽  
И.С. Караваев ◽  
М.С. Рогачев ◽  
Ю.И. Штерн ◽  
Б.Р. Мустафоев ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Electrical Resistance ◽  
Electrical Contact ◽  
Specific Contact Resistance ◽  
Electrical Contact Resistance ◽  
Semiconductor Interface ◽  
Tunneling Mechanism ◽  
Specific Contact ◽  
Transient Contact ◽  
Methods Of Measurement

The electrical contact resistance significantly affects the efficiency of thermoelements. In the case of high doped thermoelectric materials, the tunneling mechanism of conductivity prevails at metal-semiconductor interface, which makes it possible to obtain a contact resistance of less than 10-8 Ohm•m2. Low resistance values significantly complicate its experimental determination. Work present three techniques and a measuring stand for the investigation of contact resistance. The techniques are based on the measurement of the total electrical resistance, which consists of transient contact resistance and the resistance of the thermoelectric material with its subsequent exclusion. The developed techniques differ in the arrangement of the investigated contacts on the samples, in the methods of measurement and processing of the obtained results, and make it possible to determine the specific contact resistance of the order of 10-10 Ohm•m2.

Electrical Contact Resistance at the Carbon Nanotube/Pd and Carbon Nanotube/Al Interfaces in End-Contact by First-Principles Calculations

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Feng Gao ◽  
Jianmin Qu ◽  
Matthew Yao
Keyword(s):  
Electronic Structure ◽  
Carbon Nanotube ◽  
Contact Resistance ◽  
Density Functional ◽  
Electrical Contact ◽  
Electrical Contact Resistance ◽  
Functional Theory ◽  
Single Walled Carbon Nanotube ◽  
Current Voltage ◽  
Current Voltage Relation

Reported in this paper is a quantum mechanics study on the electronic structure and contact resistance at the interfaces formed when an open-end single-walled carbon nanotube (CNT) is in end-contact with aluminum (Al) and palladium (Pd), respectively. The electronic structures are computed using a density functional theory (DFT), and the transmission coefficient is calculated using a nonequilibrium Green’s function (NEGF) in conjunction with the DFT. The current–voltage relation of the simulating cell is obtained by using the Landauer–Buttiker formula, from which the contact resistance can be determined. Our results show that the electronic structure and electron transport behavior are strongly dependent on the electrode. It is found that the CNT/Pd interface has a weaker bond than the CNT/Al interface. However, the CNT/Pd interface shows a lower electrical contact resistance.

Low Resistance Ti-Si-C Ohmic Contacts for 4H-SiC Power Devices Using Laser Annealing

2017 ◽  
Vol 897 ◽  
pp. 399-402 ◽  
Author(s):  
Milantha de Silva ◽  
Teruhisa Kawasaki ◽  
Takamaro Kikkawa ◽  
Shinichiro Kuroki
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
Laser Annealing ◽  
Electrical Contact ◽  
Nickel Silicide ◽  
Specific Contact Resistance ◽  
Low Resistance ◽  
Specific Contact ◽  
Face Side ◽  
Non Equilibrium

Non-equilibrium laser silicidations for low-resistance ohmic contact to 4H-SiC C-face with Titanium was demonstrated. Ti is one of carbon-interstitial type metals. In a conventional nickel silicide (NiSi) electrode on SiC, a carbon agglomeration at the silicide/SiC interface occurs, and contact resistance becomes larger. For suppressing the carbon agglomeration, in this research, nanoseconds non-equilibrium laser annealing was introduced, and also Ti was introduced to form both silicide and carbide. Ti (75, 100 nm)/SiC and Ni (75, 100 nm)/SiC contacts were formed on C-face side of 4H-SiC substrates. Electrical contact properties were investigated after 40 nanoseconds pulse laser annealing in Ar ambient and rapid thermal annealing. As the result, In the case of laser annealing, the lowest specific contact resistance of 2.4×10-4 Ωcm2 was obtained in Ti (75 nm)/SiC sample in the laser power of 2.5 J/cm2.

Optimization of Pd/Zn/Pd/Au Ohmic Contacts to p-Type inGaAs/ InP

1994 ◽  
Vol 337 ◽  
Author(s):  
Patrick W Leech ◽  
Geoffrey K. Reeves
Keyword(s):  
Thermal Stability ◽  
Electrical Properties ◽  
Contact Resistance ◽  
Ohmic Contacts ◽  
Critical Thickness ◽  
Specific Contact Resistance ◽  
Zn Doping ◽  
Specific Contact ◽  
P Type ◽  
Thermal Stability Of

ABSTRACTThe electrical properties of Pd/Zn/Pd/Au based ohmic contacts to p-type In0 47Ga0 53As/ InP with an interposed superlattice of 50Å In047Gao 53As/ 50 Å InP have been investigated. In this study, several configurations of the Pd/Zn/Pd/Au metallization were fabricated with varying thicknesses of the Zn and interfacial Pd layers in the range 0 to 400 Å. The lowest values of specific contact resistance, ρc, were 1.2 x 10-5 Ω cm2 as-deposited and 7.5 x 106 Ω cm2 for samples annealed at 500 °C. In the as-deposited structures, ρc was reduced by an increase in thickness of both the Zn and Pd layers to 300 Å. For annealed samples, a critical thickness of the Zn ≥ 50 Å and Pd ≥ 100 Å layers was required in order to significantly reduce the magnitude of ρc. These results are consistent with a model of Pd/Zn contacts based on Zn doping of the interface. Studies of thermal stability of the contacts at 400 °C and 500 °C have shown that the Zn/Pd/Au and Pd/Zn/Pd/Au configurations were significanty lower in ρc at extended ageing times than the Pd/Au contacts.

Characteristics of Ti/Pt/Au Ohmic Contacts on p-type GaN/AlxGa1-xN Superlattices

1999 ◽  
Vol 595 ◽  
Author(s):  
L. Zhou ◽  
F. Khan ◽  
A.T. Ping ◽  
A. Osinski ◽  
I. Adesida
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
Specific Contact Resistance ◽  
Current Voltage ◽  
Specific Contact ◽  
Superlattice Structures ◽  
P Type

AbstractTi/Pt/Au metallization on p-type GaN/AlxGa1-xN (x=0.10 and 0.20) superlattices (SL) were investigated as ohmic contacts. Current-voltage and specific contact resistance measurements indicate enhanced p-type doping in the superlattice structures compared to that in GaN. Ti/Pt/Au is shown to be an effective ohmic metallization scheme on p-type GaN/AlxGa1-xN superlattices. A specific contact resistance of Rc = 4.6×10-4 Ω-cm2 is achieved for unalloyed Ti/Pt/Au on GaN/Al0.2Ga0.8N SL. This is reduced to 1.3×10-4 Ω-cm2 after annealing for 5 minutes at 300 °C.

scholarly journals Specific contact resistance of ohmic contacts to n-type SiC membranes

2011 ◽  
Vol 1335 ◽  
Author(s):  
N.F. Mohd Nasir ◽  
A.S. Holland ◽  
G.K. Reeves ◽  
P.W. Leech ◽  
A. Collins ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
Current Flow ◽  
Specific Contact Resistance ◽  
Voltage Response ◽  
Metal Contacts ◽  
Transmission Line Model ◽  
Si Substrate ◽  
Current Voltage ◽  
Specific Contact

ABSTRACTMembranes of epitaxial SiC have been used as a means of eliminating the leakage current into the Si substrate during circular transmission line model (CTLM) measurements. In the n+-3C-SiC/Si wafers, the Si substrate was etched in a patterned window with dimensions up to 10 mm × 15 mm2. An array of CTLM metal contacts was then deposited onto the upper surface of the n+-SiC membrane. The CTLM contacts on the membrane have shown an ohmic current/voltage response while electrodes located on the adjacent substrate were non-ohmic. Values of ρc were measured directly on the membranes. These results have shown a significant increase in the current flow below the metal contacts due to the presence of the Si substrate.

scholarly journals Fabrication of Skutterudite-Based Tubular Thermoelectric Generator

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1106 ◽  
Author(s):  
Hanhwi Jang ◽  
Jong Bae Kim ◽  
Abbey Stanley ◽  
Suhyeon Lee ◽  
Yeongseon Kim ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Thermoelectric Generator ◽  
Thermal Contact ◽  
Electrical Contact ◽  
Specific Contact Resistance ◽  
Electrical Contact Resistance ◽  
Plasma Sintering ◽  
Planar Substrate ◽  
Specific Contact ◽  
Tubular Thermoelectric Generator

The conversion efficiency of the thermoelectric generator (TEG) is adversely affected by the quality of thermal contact between the module and the heat source. TEGs with the planar substrate are not suitable for the curved heat sources. Several attempts have been made to tackle this issue by fabricating complex tubular-shaped TEGs; however, all efforts have been limited to low-temperature applications. Furthermore, the electrical contact resistance of the module is critical to achieving a high-power output. In this work, we developed the tubular TEG with significantly low specific contact resistance by optimizing the joining process. We show that the modified resistance welding (MRW) performed by spark plasma sintering (SPS) is an efficient joining method for the fabrication of the TE module, with high feasibility and scalability. This research seeks to suggest important design rules to consider when fabricating TEGs.

scholarly journals Characteristics of Ti/Pt/Au Ohmic Contacts on p-type GaN/AlxGa1−xN Superlattices

2000 ◽  
Vol 5 (S1) ◽  
pp. 514-520
Author(s):  
L. Zhou ◽  
F. Khan ◽  
A.T. Ping ◽  
A. Osinsk ◽  
I. Adesida
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
Specific Contact Resistance ◽  
Current Voltage ◽  
Specific Contact ◽  
Superlattice Structures ◽  
P Type

Ti/Pt/Au metallization on p-type GaN/AlxGa1−xN (x=0.10 and 0.20) superlattices (SL) were investigated as ohmic contacts. Current-voltage and specific contact resistance measurements indicate enhanced p-type doping in the superlattice structures compared to that in GaN. Ti/Pt/Au is shown to be an effective ohmic metallization scheme on p-type GaN/AlxGa1−xN superlattices. A specific contact resistance of Rc = 4.6×10−4 ω-cm2 is achieved for unalloyed Ti/Pt/Au on GaN/Al0.2Ga0.8N SL. This is reduced to 1.3×10−4 ω-cm2 after annealing for 5 minutes at 300 °C.

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