Wyniki wyszukiwania - BazTech

1

Structural Deformation of Tungsten Diselenide Nanostructures Induced by Ozone Oxidation and Investigation of Electronic Properties Change

Kim Eunjeong, Lee Sangyoeb, Je Yeonjin, Lee Dong Park, Park Sang Jun, Jeong Sanghyun, Park Joon Sik, Ahn Byungmin, Park Jun Hong

Archives of Metallurgy and Materials

|

2022

|

Vol. 67, iss. 4

1469--1473

EN

Tungsten diselenide (WSe2) is one of the promising transition metal dichalcogenides (TMDs) for nanoelectronics and opto-electronics. To enhance and tune the electronic performance of TMDs, chemical functionalization via covalent and van der Waals approaches has been suggested. In the present report, the electric and structural transition of WSe2 oxidized by exposure to O3 is investigated using scanning tunneling microscopy. It is demonstrated that the exposure of WSe2/high-ordered pyrolytic graphite sample to O3 induces the formation of molecular adsorbates on the surface, which enables to increase in the density of states near the valence band edge, resulting from electric structural modification of domain boundaries via exposure of atomic O. According to the work function extracted by Kelvin probe force microscopy, monolayer WSe2 with the O3 exposure results in a gradual increase in work function as the exposure to O3. Therefore, the present report demonstrates the potential pathway for the chemical functionalization of TMDs to enhance the electric performance of TMDs devices.

2

Functionalization of the Si(1 1 1) 7 × 7 substrate with coronene molecules using simple molecular source

Przychodnia M., Czajka R., Koczorowski W.

Materials Science Poland

|

2018

|

Vol. 36, No. 1

86--92

EN

The present paper aims at describing a source designed and constructed to generate an organic molecular beam under ultrahigh vacuum conditions. The presented construction solution of the evaporation source allows for independent deposition of three different kinds of molecules. The probability of molecules fragmentation is minimized by using a thermocouple being in contact with a molecular crucible, which enables precise temperature control. In addition, cleanness and molecular beam density are monitored using a quadrupole mass spectrometer and quartz microbalance, respectively. The operational parameters of the molecular source are optimized and deposition rates are measured for the coronene molecule in the sublimation temperature range between 430 K and 460 K. The analysis of scanning tunneling microscope images of the Si(1 1 1) 7 × 7 substrate covered with the sub-monolayer of coronene molecules and comparison with previously published data has been used for verification of the molecular source operation.

3

STM study of nanostructures grown on Ag/Si(111)-√3×√3 surface evaporated by 8.7 ML Ni

Tomaszewska A.

Prace Naukowe Akademii im. Jana Długosza w Częstochowie. Technika, Informatyka, Inżynieria Bezpieczeństwa

|

2016

|

T. 4

469--476

EN

The thermo-evolution of the interface obtained by room temperature (RT) deposition of 8.7 ML Ni onto an Ag/Si(111)-√3×√3 surface has been studied with the use of scanning tunneling microscopy. Annealing the surface within RT- 573 K temperature range leads to the increase in surface roughness which is followed by its drop upon annealing at 673 K. The comparison of the images presented here with those published for both submonolayer Ni and 4.2 ML Ni indicates coverage-dependent features.

PL

Ewolucja termiczna interfejsu otrzymanego w wyniku osadzenia 8.7 ML Ni na powierzchni Ag/Si(111)-√3×√3 w temperaturze pokojowej (RT) badana była przy użyciu skaningowej mikroskopii tunelowej. Wygrzewanie powierzchni w zakresie temperatur RT- 573 K prowadzi do wzrostu szorstkości powierzchni, po czym w temperaturze 673 K następuje jej spadek. Porównanie obrazów prezentowanych w niniejszej pracy z obrazami opublikowanymi dla pokryć Ni niższych niż 1 monowarstwa oraz dla pokrycia 4.2 ML wskazuje na występowanie cechy zależnych od pokryć.

4

Thermal evolution of the morphology of Ni/Ge(111)-c(2 × 8) surface

Tomaszewska A., Li J. H., Huang X. L., Fu T. Y.

Materials Science Poland

|

2014

|

Vol. 32, No. 4

641--647

EN

The thermal evolution of the interface formed by room temperature (RT) deposition of Ni atoms (coverage 0.1, 0.5, 1.2 ML) onto a Ge(111)-c(2 × 8) surface has been studied with the use of scanning tunneling microscopy (STM). Atomically resolved STM images revealed that, at RT, the boundaries between the different c(2 × 8) domains acted as nucleation sites for Ni atoms. After annealing the surface with deposited material at 473 to 673 K the formation of nano-sized islands of NixGey compounds was observed. In addition, the occurrence of ring-like structures was recorded. Based on the dual-polarity images the latter were assigned to Ni atoms adsorbed on Ge adatoms.

5

New Methods to Study Thin Organic Films at Electrode Surfaces

Zawisza I., Cai X., Zamlynny V., Burgess I., Majewski J., Szymański G., Lipkowski J.

Polish Journal of Chemistry

|

2004

|

Vol. 78 / nr 9

1165-1181

EN

Chronocoulometry, scanning tunneling microscopy (STM), neutron reflectometry (NR) and in situ polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) have been employed to study the properties of a monolayer of n-octadecanol at a Au(111) electrode surface. Chronocoulometry has been used to determine the charge density at the electrode surface covered by the film of n-octadecanol. The surface pressure of this film was calculated from the charge density data. The film pressure data were used to describe the film properties at the gold solution interface. It has been found that at film pressures larger than 12 mNm-1 the monolayer is in a compressed state and at lower film pressures in a decompressed state. STM imaging, NR and PM-IRRAS have been employed to determine the nature of the two states.We have demonstrated that the properties of a monolayer of n-octadecanol at the metal-solution interface display many similarities to the properties of an equivalent film at the air-solution interface.

6

The electrochemical scanning tunneling microscopy of the polycrystalline nickel oxidation in sulphuric acid solutions

Błaszczyk T., Kaźmierczak D., Krzyczmonik P., Scholl H.

Polish Journal of Chemistry

|

1998

|

Vol. 72, nr 9

2134-2143

EN

A home-made Electrochemical Scanning Tunneling Microscope/Scanning Tunneling Microscope (ESTM/STM) has been used for investigations of the anodic oxidation of polycrystalline nickel, being controlled by cyclic voltammetry and coulometry. A surface fragment with a(+/-)10% accuracy at the scale of 4800 nm x 4800 nm and 100 nm x 100 nm was observed. The best compact and relatively smooth layers of nickel oxides have been obtained in a concentrated (c=10.0 mol dm(-3)) sulphuric acid solution. In a diluted electrolyte (c=0.1 mol dm(-3)), the formation of the NiO-x islands is possible.