Low‐Damaged Layer‐by‐Layer Etching of Large‐Area Molybdenum Disulfide Films via Mild Plasma Treatment

2020 ◽  
Vol 7 (17) ◽  
pp. 2000762
Author(s):  
Sang‐Soo Chee ◽  
Moon‐Ho Ham
Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1860
Author(s):  
Won Seok Seo ◽  
Dae Ki Kim ◽  
Ji-Hoon Han ◽  
Kang-Bak Park ◽  
Su Chak Ryu ◽  
...  

Monolayer and multilayer molybdenum disulfide (MoS2) materials are semiconductors with direct/indirect bandgaps of 1.2–1.8 eV and are attractive due to their changes in response to electrical, physicochemical, biological, and mechanical factors. Since the desired electrical properties of MoS2 are known, research on its electrical properties has increased, with focus on the deposition and growth of large-area MoS2 and its functionalization. While research on the large-scale production of MoS2 is actively underway, there is a lack of studies on functionalization approaches, which are essential since functional groups can help to dissolve particles or provide adequate reactivity. Strategies for producing films of functionalized MoS2 are rare, and what methods do exist are either complex or inefficient. This work introduces an efficient way to functionalize MoS2. Functional groups are formed on the surface by exposing MoS2 with surface sulfur vacancies generated by plasma treatment to 3-mercaptopropionic acid. This technique can create 1.8 times as many carboxyl groups on the MoS2 surface compared with previously reported strategies. The MoS2-based gas sensor fabricated using the proposed method shows a 2.6 times higher sensitivity and much lower detection limit than the untreated device.


2019 ◽  
Vol 43 (12) ◽  
pp. 4900-4907 ◽  
Author(s):  
Dongzhi Zhang ◽  
Maosong Pang ◽  
Junfeng Wu ◽  
Yuhua Cao

A high-performance sulfur dioxide sensor based on a platinum-loaded titanium dioxide/molybdenum disulfide ternary nanocomposite is synthesized via layer-by-layer self-assembly.


2017 ◽  
Vol 56 (11) ◽  
pp. 110302
Author(s):  
Ja-Yeon Kim ◽  
Doo-Hyung Kim ◽  
Min-Ki Kwon

2019 ◽  
Vol 3 (2) ◽  
pp. 30 ◽  
Author(s):  
Mohsen Ziaee ◽  
Rebecca Hershman ◽  
Ayesha Mahmood ◽  
Nathan B. Crane

Cadaveric decellularized bone tissue is utilized as an allograft in many musculoskeletal surgical procedures. Typically, the allograft acts as a scaffold to guide tissue regeneration with superior biocompatibility relative to synthetic scaffolds. Traditionally these scaffolds are machined into the required dimensions and shapes. However, the geometrical simplicity and, in some cases, limited dimensions of the donated tissue restrict the use of allograft scaffolds. This could be overcome by additive manufacturing using granulated bone that is both decellularized and demineralized. In this study, the large area projection sintering (LAPS) method is evaluated as a fabrication method to build porous structures composed of granulated cortical bone bound by polycaprolactone (PCL). This additive manufacturing method utilizes visible light to selectively cure the deposited material layer-by-layer to create 3D geometry. First, the spreading behavior of the composite mixtures is evaluated and the conditions to attain improved powder bed density to fabricate the test specimens are determined. The tensile strength of the LAPS fabricated samples in both dry and hydrated states are determined and compared to the demineralized cancellous bone allograft and the heat treated demineralized-bone/PCL mixture in mold. The results indicated that the projection sintered composites of 45–55 wt %. Demineralized bone matrix (DBM) particulates produced strength comparable to processed and demineralized cancellous bone.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Yuanyuan Zhao ◽  
Peifei Tong ◽  
Dong Ma ◽  
Bing Li ◽  
Qinzhuang Liu ◽  
...  

Design and synthesis of ZnO@TiO2 core-shell nanorod arrays as promising photocatalysts have been widely reported. However, it remains a challenge to develop a low-temperature, low-cost, and environmentally friendly method to prepare ZnO@TiO2 core-shell nanorod arrays over a large area for future device applications. Here, a facile, green, and efficient route is designed to prepare the ZnO@TiO2 nanorod arrays with a highly uniform core-shell structure over a large area on Zn wafer via a vapor-thermal method at relatively low temperature. The growth mechanism is proposed as a layer-by-layer assembly. The photocatalytic decomposition reaction of methylene blue (MB) reveals that the ZnO@TiO2 core-shell nanorod arrays have excellent photocatalytic activities when compared with the performance of the ZnO nanorod arrays. The improved photocatalytic activity could be attributed to the core-shell structure, which can effectively reduce the recombination rate of electron-hole pairs, significantly increase the optical absorption range, and offer a high density of surface active catalytic sites for the decomposition of organic pollutants. In addition, it is very easy to separate or recover ZnO@TiO2 core-shell nanorod array catalysts when they are used in water purification processes.


2001 ◽  
Vol 685 ◽  
Author(s):  
Ting-Kuo Chang ◽  
Ching-Wei Lin ◽  
Chang-Ho Tseng ◽  
Huang-Chung Cheng ◽  
Yuan-Ching Peng ◽  
...  

AbstractIn this work, high quality silicon dioxide (SiO2) films were prepared by large-area plasmaenhanced chemical vapor deposition (LA-PECVD) using tetraethylorthosilicate(TEOS)-oxygen based chemistry. The effects of various short-time plasma treatments on these as-deposited TEOS oxide were also investigated. Different plasma treatments such as O2, N2O, and NH3 were used in our experiments. Electrical characteristics were exploited to examine the effects of plasma treatments. It was shown that after N2O, and NH3 plasma treatments, the electrical strength of oxide was enhanced. Besides, NH3 plasma treatment exhibited the highest enhancement efficiency. O2- plasma treatment, however, showed some harmful effects on the electrical properties of the TEOS oxide. The reliability tests including charge to breakdown (Qbd) and bias temperature stress (BTS) were also analyzed in these samples. Although better pre-stress characteristics were observed in those samples treated by NH3-plasma, samples with N2O plasma treatment showed superior stress endurance. Consequently, N2O plasma treatment seems to be the best candidate for future TFTs under the consideration of long-term reliability.


2014 ◽  
Vol 668-669 ◽  
pp. 818-821
Author(s):  
Hai Yan Wang ◽  
Ya Ting Zhang ◽  
Xiao Xian Song ◽  
Lu Fan Jin ◽  
Hai Tao Dai ◽  
...  

With the breakthrough of mobility in quantum dot electric field transistors (Q-EFTs), the potential application in these functional devices has revealed and been paid more attentions, due to flexibility in design, low cost, facility for processing and large area. One of the most important applications of FETs is the photoconductive detector. However, these functional FETs have less been reported. In this work, colloidal PbS Q-FETs were successfully fabricated by reasonable structure design and layer-by-layer depositon technique PbS quantum-dots. The bipolar property was demonstrated by the output and transfer characteristics, as devices work in I and III quadrants simultaneously. The mobilities of electron and hole are 0.16 cm2/(V⋅s) and 0.28 cm2/(V⋅s), respectively. Q-FETs work as photoconductive detectors at both positive and negative gate bias voltages. Under constant gate bias, photocurrent increase exponentially with the intensity of light. The responding region consisted with the absorption range of PbS quantum dots. A linearity was found in drain voltage and incidence of laser power, the ratio was attributing to 0.0019 (μW⋅V)-1.


2021 ◽  
Author(s):  
David Moss

Abstract Layered two-dimensional (2D) graphene oxide (GO) films are integrated with micro-ring resonators (MRRs) to experimentally demonstrate enhanced nonlinear optics in the form of four-wave mixing (FWM). Both uniformly coated and patterned GO films are integrated on CMOS-compatible doped silica MRRs using a large-area, transfer-free, layer-by-layer GO coating method together with photolithography and lift-off processes, yielding precise control of the film thickness, placement, and coating length. The high Kerr nonlinearity and low loss of the GO films combined with the strong light-matter interaction within the MRRs results in a significant improvement in the FWM efficiency in the hybrid MRRs. Detailed FWM measurements are performed at different pump powers and resonant wavelengths for the uniformly coated MRRs with 1 − 5 layers of GO as well as the patterned devices with 10 − 50 layers of GO. The experimental results show good agreement with theory, achieving up to ~ 7.6-dB enhancement in the FWM conversion efficiency (CE) for an MRR uniformly coated with 1 layer of GO and ~ 10.3-dB for a patterned device with 50 layers of GO. By fitting the measured CE as a function of pump power for devices with different numbers of GO layers, we also extract the dependence of GO’s third-order nonlinearity on layer number and pump power, revealing interesting physical insights about the evolution of the layered GO films from 2D monolayers to quasi bulk-like behavior. These results confirm the high nonlinear optical performance of integrated photonic resonators incorporated with 2D layered GO films.


Sign in / Sign up

Export Citation Format

Share Document