Low Voltage and Ferroelectric 2D Electron Devices Using Lead‐Free Ba x Sr 1‐x TiO 3 and MoS 2 Channel

2019 ◽  
Vol 30 (7) ◽  
pp. 1908210 ◽  
Author(s):  
Yeonsu Jeong ◽  
Hye‐Jin Jin ◽  
Ji Hoon Park ◽  
Yongjae Cho ◽  
Minju Kim ◽  
...  
1994 ◽  
Author(s):  
Yuri V. Gulyaev ◽  
I. S. Nefyodov ◽  
A. V. Nechaev ◽  
Nickolay I. Sinitsyn ◽  
Gennadii V. Torgashov ◽  
...  

1973 ◽  
Vol 16 (11) ◽  
pp. 1374-1376
Author(s):  
S. G. Afanasov ◽  
I. Ya. Ashbel' ◽  
B. M. Zhulkovskii ◽  
V. I. Kochetkov ◽  
S. G. Petrov ◽  
...  

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5446
Author(s):  
Subin Lee ◽  
Soyeon Kwak ◽  
Taehyun Park ◽  
Byoungchul Son ◽  
Hyung Joong Yun ◽  
...  

Perovskite is attracting considerable interest because of its excellent semiconducting properties and optoelectronic performance. In particular, lead perovskites have been used extensively in photovoltaic, photodetectors, thin-film transistors, and various electronic applications. On the other hand, the elimination of lead is essential because of its strong toxicity. This paper reports the synthesis of lead-free calcium titanate perovskite (CaTiO3) using a solution-processed combustion method. The chemical and morphological properties of CaTiO3 were examined as a function of its thickness by scanning electron microscopy, X-ray diffraction (XRD), atomic force microscopy, X-ray photoelectron spectroscopy, and ultraviolet–visible spectrophotometry. The analysis showed that thicker films formed by a cumulative coating result in larger grains and more oxygen vacancies. Furthermore, thickness-dependent hysteresis behaviors were examined by fabricating a metal-CaTiO3-metal structure. The electrical hysteresis could be controlled over an extremely low voltage operation, as low as 100 mV, by varying the grain size and oxygen vacancies.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hong Chen ◽  
Lin Zhu ◽  
Chen Xue ◽  
Pinlei Liu ◽  
Xuerong Du ◽  
...  

AbstractSolution-processed metal-halide perovskites are emerging as one of the most promising materials for displays, lighting and energy generation. Currently, the best-performing perovskite optoelectronic devices are based on lead halides and the lead toxicity severely restricts their practical applications. Moreover, efficient white electroluminescence from broadband-emission metal halides remains a challenge. Here we demonstrate efficient and bright lead-free LEDs based on cesium copper halides enabled by introducing an organic additive (Tween, polyethylene glycol sorbitan monooleate) into the precursor solutions. We find the additive can reduce the trap states, enhancing the photoluminescence quantum efficiency of the metal halide films, and increase the surface potential, facilitating the hole injection and transport in the LEDs. Consequently, we achieve warm-white LEDs reaching an external quantum efficiency of 3.1% and a luminance of 1570 cd m−2 at a low voltage of 5.4 V, showing great promise of lead-free metal halides for solution-processed white LED applications.


Author(s):  
Marek Malecki ◽  
J. Victor Small ◽  
James Pawley

The relative roles of adhesion and locomotion in malignancy have yet to be clearly established. In a tumor, subpopulations of cells may be recognized according to their capacity to invade neighbouring tissue,or to enter the blood stream and metastasize. The mechanisms of adhesion and locomotion are themselves tightly linked to the cytoskeletal apparatus and cell surface topology, including expression of integrin receptors. In our studies on melanomas with Fluorescent Microscopy (FM) and Cell Sorter(FACS), we noticed that cells in cultures derived from metastases had more numerous actin bundles, then cells from primary foci. Following this track, we attempted to develop technology allowing to compare ultrastructure of these cells using correlative Transmission Electron Microscopy(TEM) and Low Voltage Scanning Electron Microscopy(LVSEM).


Author(s):  
Marek Malecki ◽  
James Pawley ◽  
Hans Ris

The ultrastructure of cells suspended in physiological fluids or cell culture media can only be studied if the living processes are stopped while the cells remain in suspension. Attachment of living cells to carrier surfaces to facilitate further processing for electron microscopy produces a rapid reorganization of cell structure eradicating most traces of the structures present when the cells were in suspension. The structure of cells in suspension can be immobilized by either chemical fixation or, much faster, by rapid freezing (cryo-immobilization). The fixation speed is particularly important in studies of cell surface reorganization over time. High pressure freezing provides conditions where specimens up to 500μm thick can be frozen in milliseconds without ice crystal damage. This volume is sufficient for cells to remain in suspension until frozen. However, special procedures are needed to assure that the unattached cells are not lost during subsequent processing for LVSEM or HVEM using freeze-substitution or freeze drying. We recently developed such a procedure.


Author(s):  
T. Miyokawa ◽  
S. Norioka ◽  
S. Goto

Field emission SEMs (FE-SEMs) are becoming popular due to their high resolution needs. In the field of semiconductor product, it is demanded to use the low accelerating voltage FE-SEM to avoid the electron irradiation damage and the electron charging up on samples. However the accelerating voltage of usual SEM with FE-gun is limited until 1 kV, which is not enough small for the present demands, because the virtual source goes far from the tip in lower accelerating voltages. This virtual source position depends on the shape of the electrostatic lens. So, we investigated several types of electrostatic lenses to be applicable to the lower accelerating voltage. In the result, it is found a field emission gun with a conical anode is effectively applied for a wide range of low accelerating voltages.A field emission gun usually consists of a field emission tip (cold cathode) and the Butler type electrostatic lens.


Author(s):  
E. F. Lindsey ◽  
C. W. Price ◽  
E. L. Pierce ◽  
E. J. Hsieh

Columnar structures produced by DC magnetron sputtering can be altered by using RF biased sputtering or by exposing the film to nitrogen pulses during sputtering, and these techniques are being evaluated to refine the grain structure in sputtered beryllium films deposited on fused silica substrates. Beryllium is brittle, and fractures in sputtered beryllium films tend to be intergranular; therefore, a convenient technique to analyze grain structure in these films is to fracture the coated specimens and examine them in an SEM. However, fine structure in sputtered deposits is difficult to image in an SEM, and both the low density and the low secondary electron emission coefficient of beryllium seriously compound this problem. Secondary electron emission can be improved by coating beryllium with Au or Au-Pd, and coating also was required to overcome severe charging of the fused silica substrate even at low voltage. The coating structure can obliterate much of the fine structure in beryllium films, but reasonable results were obtained by using the high-resolution capability of an Hitachi S-800 SEM and either ion-beam coating with Au-Pd or carbon coating by thermal evaporation.


Author(s):  
Zhifeng Shao

Recently, low voltage (≤5kV) scanning electron microscopes have become popular because of their unprecedented advantages, such as minimized charging effects and smaller specimen damage, etc. Perhaps the most important advantage of LVSEM is that they may be able to provide ultrahigh resolution since the interaction volume decreases when electron energy is reduced. It is obvious that no matter how low the operating voltage is, the resolution is always poorer than the probe radius. To achieve 10Å resolution at 5kV (including non-local effects), we would require a probe radius of 5∽6 Å. At low voltages, we can no longer ignore the effects of chromatic aberration because of the increased ratio δV/V. The 3rd order spherical aberration is another major limiting factor. The optimized aperture should be calculated as


Author(s):  
M. Osumi ◽  
N. Yamada ◽  
T. Nagatani

Even though many early workers had suggested the use of lower voltages to increase topographic contrast and to reduce specimen charging and beam damage, we did not usually operate in the conventional scanning electron microscope at low voltage because of the poor resolution, especially of bioligical specimens. However, the development of the “in-lens” field emission scanning electron microscope (FESEM) has led to marked inprovement in resolution, especially in the range of 1-5 kV, within the past year. The probe size has been cumulated to be 0.7nm in diameter at 30kV and about 3nm at 1kV. We have been trying to develop techniques to use this in-lens FESEM at low voltage (LVSEM) for direct observation of totally uncoated biological specimens and have developed the LVSEM method for the biological field.


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