scholarly journals Влияние контактной разности потенциалов на вольт-амперные характеристики в сканирующей туннельной спектроскопии

2021 ◽  
Vol 91 (11) ◽  
pp. 1769
Author(s):  
М.В. Кузьмин ◽  
М.А. Митцев
Keyword(s):  
Contact Potential Difference ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Differential Conductivity ◽  
Contact Potential ◽  
Potential Barriers ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Work Functions ◽  
Conductivity Spectra

Using the energy diagrams of asymmetric potential barriers formed at the contact of two metals with different work functions, the influence of contact potential difference on the current-voltage characteristics and differential conductivity spectra measured by scanning tunneling spectroscopy is considered. It is shown that the obtained conclusions are in qualitative agreement with the experimental results for ytterbium nanofilms with the thickness of 16 monolayers (6.08 nm). However, they significantly differ quantitatively. The analysis of such diffrences is performed.

SCANNING TUNNELING SPECTROSCOPY ON THE GdSr2RuCu2O8 COMPOUND

2003 ◽  
Vol 17 (04n06) ◽  
pp. 608-613 ◽  
Author(s):  
F. BOBBA ◽  
F. GIUBILEO ◽  
M. GOMBOS ◽  
C. NOCE ◽  
A. VECCHIONE ◽  
...  
Keyword(s):  
Coulomb Blockade ◽  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Tunneling Conductance ◽  
Zero Bias ◽  
Voltage Range ◽  
Current Voltage ◽  
Spectroscopic Information ◽  
Current Voltage Characteristics

Topographic and spectroscopic information on GdSr2RuCu2O8 sintered pellets have been obtained by a home built low temperature Scanning Tunneling Microscope (STM) operating at 4.2 K. The topographic image of the surface showed non homogeneous samples with grains of typical size of about 100 nm. In many locations studied, the Tunneling Spectroscopy reveals the presence of charging effects in the current-voltage characteristics over a voltage range up to 100 mV. Two types of charging effects are clearly distinguished: one corresponds to the reduction of the tunneling conductance around zero bias and is attributed to the Coulomb blockade, and another onw, a stepwise increasing of the current as a function of the bias voltage is identified as Coulomb staircase regime. Besides these spurious charging effects, the current-voltage characteristics often show a pronounced non-linearity around 4.0 mV. This non-linearity, disappearing above the critical temperature of the materials, is connected to the superconducting gap in the GdSr 2 RuCu 2 O 8.

Functional Characteristics of QD-InAs/GaAs Heterostructures with Potential Barriers AlGaAs and GaAs

2018 ◽  
Vol 284 ◽  
pp. 182-187
Author(s):  
E.E. Blokhin ◽  
D.A. Arustamyan ◽  
L.M. Goncharova
Keyword(s):  
Quantum Dots ◽  
High Speed ◽  
Ion Beam ◽  
Inas Quantum Dots ◽  
Potential Barriers ◽  
Near Ir ◽  
Current Voltage ◽  
Ir Photodetectors ◽  
Current Voltage Characteristics ◽  
Beam Deposition

In this paper we present the results of investigation of heterostructures with an array of InAs quantum dots grown on GaAs substrates with GaAs and AlGaAs front barriers for high-speed near-IR photodetectors. The thickness of the barrier layers did not exceed 30 nm. It is shown that the ion-beam deposition method makes it possible to grow quantum dots with lateral dimensions up to 30 nm and 15 nm height. The spectral dependences of the external quantum efficiency and dark current-voltage characteristics are investigated.

Comparative Surface Studies at Atomic Resolution with Ultrahigh Vacuum Variable-Temperature Atomic Force and Scanning Tunneling Microscopes

1999 ◽  
Vol 5 (3) ◽  
pp. 208-215 ◽  
Author(s):  
Masashi Iwatsuki ◽  
Kazuyuki Suzuki ◽  
Shin-ich Kitamura ◽  
Mike Kersker
Keyword(s):  
Detection Method ◽  
Variable Temperature ◽  
Contact Potential Difference ◽  
Oscillation Amplitude ◽  
Ultrahigh Vacuum ◽  
Atomic Resolution ◽  
Scanning Tunneling ◽  
Contact Potential ◽  
Atomic Force ◽  
Temperature Scanning

With the ultrahigh vacuum variable-temperature scanning tunneling microscope (UHV-VT-STM), atomic-level observation has been achieved. An ultrahigh vacuum atomic force microscope (UHV-AFM) has also been developed, with success in obtaining atom images where observation in noncontact (NC) mode with a frequency modulation (FM) detection method was attempted. Using the FM detection method in the constant oscillation amplitude of the cantilever excitation mode, we have obtained atomic-resolution images of Si(111) 7 × 7 structures and Si(100) 2 × 1 structures and other structures together with STM images in an ultrahigh vacuum environment. Also shown here are contact potential difference (CPD) images using the NC-AFM method.

Irregular Electron Transport Through a-Si:H Based Potential Barriers

1993 ◽  
Vol 297 ◽  
Author(s):  
Norbert Bernhard ◽  
B. Frank ◽  
B. Movaghar ◽  
G.H. Bauer
Keyword(s):  
Electron Transport ◽  
Transport Mechanism ◽  
Current Transport ◽  
Transport Mechanisms ◽  
Potential Barriers ◽  
Resonant Tunnelling ◽  
Current Voltage ◽  
Different Temperatures ◽  
Current Voltage Characteristics ◽  
Stable Formation

Irregularities in the current-voltage-characteristics of a-Si:H based potential barriers have been investigated experimentally, and are discussed theoretically with respect to different transport mechanisms. The investigated samples were different series of double and single barrier a-Si:H - a-Si1-xCx:H - heterostructures, as well as homogeneous samples without heterostructure barrier. Current-voltage-(I-V)-characteristics showing a wide variety of features, from complete smoothness of the curves, to bumps and even accidental step-like switching behaviour, as well as different forms of noise, were recorded at different temperatures. Resonant tunnelling as an explaining transport mechanism for the anomalies was excluded because of inconsistency between experiment and calculations partially including special amorphous features. Instead it is argued that all observed irregularities, i. e. bumps in I-V-curves, switching-like behaviour, and appearance of noise, are related to current transport via trap-assisted tunnelling through locally strongly confined transport paths, leading to the meta-stable formation, change and break-down of conductory filaments.

Schottky Barrier Height Dependence on the Metal Work Function for p-type Si Schottky Diodes

2004 ◽  
Vol 59 (11) ◽  
pp. 795-798 ◽  
Author(s):  
Güven Çankaya ◽  
Nazım Uçar
Keyword(s):  
Fermi Level ◽  
Schottky Barrier ◽  
Schottky Diodes ◽  
Metal Work Function ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Work Functions ◽  
P Type ◽  
Relationship Of ◽  
Metal Work

We investigated Schottky barrier diodes of 9 metals (Mn, Cd, Al, Bi, Pb, Sn, Sb, Fe, and Ni) having different metal work functions to p-type Si using current-voltage characteristics. Most Schottky contacts show good characteristics with an ideality factor range from 1.057 to 1.831. Based on our measurements for p-type Si, the barrier heights and metal work functions show a linear relationship of current-voltage characteristics at room temperature with a slope (S=ϕb/ϕm) of 0.162, even though the Fermi level is partially pinned. From this linear dependency, the density of interface states was determined to be about 4.5 · 1013 1/eV per cm2, and the average pinning position of the Fermi level as 0.661 eV below the conduction band

CURRENT–VOLTAGE PROPERTIES OF SELF-ASSEMBLY MONOLAYERS ON AU(111) SUBSTRATE USING SCANNING TUNNELING MICROSCOPY

2006 ◽  
Vol 05 (06) ◽  
pp. 907-911
Author(s):  
NAM-SUK LEE ◽  
HOON-KYU SHIN ◽  
YOUNG-SOO KWON
Keyword(s):  
Thin Film ◽  
Electrical Properties ◽  
Scanning Tunneling Microscopy ◽  
Self Assembly ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Organic Thin Film ◽  
Tunneling Microscopy ◽  
Current Voltage ◽  
Self Assembled

This study observes the morphology of self-assembled organic thin film that is formed at room temperature using a Scanning Tunneling Microscopy (STM) and examines its electrical properties using a Scanning Tunneling Spectroscopy (STS). The specimen used in this experiment that has a functional group for both sides and will be controlled to make self-assembled onto the Au (111) substrate. After the dilution of the specimen by 1 mM/ml and self-assembled onto the Au (111) substrate. Using a STM, the images of organic thin film can be observed. In addition, the electrical properties of organic thin film can also be examined by the junction structure of STM–organic thin film– Au (111) substrate by using a STM tip. As a result, we measured current–voltage (I–V) curve using STS, I–V curve also clearly shows several current peaks between the negative bias region (-1.42 V) and the positive bias region (1.30 V), respectively.

Current-Voltage Characteristics of Self-Assembled Monolayers by Scanning Tunneling Microscopy

1997 ◽  
Vol 79 (13) ◽  
pp. 2530-2533 ◽  
Author(s):  
Supriyo Datta ◽  
Weidong Tian ◽  
Seunghun Hong ◽  
R. Reifenberger ◽  
Jason I. Henderson ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Self Assembled Monolayers ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Current Voltage ◽  
Assembled Monolayers ◽  
Current Voltage Characteristics ◽  
Self Assembled

Scanning Tunneling Microscopy Imaging and Spectroscopy of a Single Viologen Molecule

2008 ◽  
Vol 8 (9) ◽  
pp. 4621-4625
Author(s):  
Nam-Suk Lee ◽  
Chang-Heon Yang ◽  
Won-Suk Choi ◽  
Young-Soo Kwon
Keyword(s):  
Self Assembly ◽  
Current Mode ◽  
Scanning Tunneling Spectroscopy ◽  
Constant Current ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Microscopy Imaging ◽  
Current Voltage ◽  
Imaging And Spectroscopy ◽  
Stm Images

A low-temperature ultrahigh-vacuum scanning tunneling microscope (UHV-STM) was used to image viologen (N-methyl-N′-di (8-mercaptooctyl)-4,4′-bipyridinium; HSC8VC8SH) molecules and to perform local spectroscopic measurements on these molecules. Self-assembly of viologen molecules was conducted on Au (111), which had been thermally deposited onto freshly cleaved, heated mica. Here, we demonstrate a novel SAM matrix appropriate for the isolation of viologen molecules composed of octanethiol (C8) in which HSC8VC8SH was inserted at defects in the molecular lattice. The isolated single molecules of viologen inserted in the SAM matrix were observed as protrusions in STM topography using a constant current mode. STM images at 298 K showed protrusions with a topographic height of about 2.71 nm (HSC8VC8SH) with viologen molecules that self-assembled on the substrate. The current–voltage (I–V) characteristics were measured while the electrical properties of the formed monolayer were scanned using scanning tunneling spectroscopy (STS). We found the high peak current-like rectification at +1.14 V (HSC8VC8SH). The rectification ratios, RR = J (at +2.5 V)/J (at −2.5 V), are in the range of 4.47.

Sign in / Sign up

Export Citation Format

Share Document