scholarly journals Growth of a Large, Single-Crystalline WS2 Monolayer for High-Performance Photodetectors by Chemical Vapor Deposition

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 137
Author(s):  
Ying Chen
Keyword(s):  
High Performance ◽  
Chemical Vapor ◽  
Fast Response ◽  
Tungstic Acid ◽  
Large Area ◽  
High Quality ◽  
Promising Candidate ◽  
Cvd Method ◽  
Ws2 Nanosheets ◽  
Ws2 Monolayer

2D WS2 is a promising candidate for the next generation nanoelectronics, spintronics, valleytronics, and optoelectronics. However, the uncontrollably large-area growth of WS2 nanosheets and their unsatisfactory performance of the photodetectors based on WS2 hindered its applications. Here, we proposed a CVD method using tungstic acid as the precursors to grow WS2 flakes. After being characterized by AFM, Raman, PL, and TEM, we found the as-grown WS2 flakes were high-quality structures. Then the photodetectors based on the as-grown WS2 were fabricated, which exhibited high responsivity (7.3 A W−1), a fast response rate (a response time of 5 ms and a recovery time of 7 ms), prefect external quantum efficiency (EQE) (1814%), and remarkable detectivity (D*) (3.4 × 1012 Jones). Our works provided a new CVD method to grow some high-quality WS2 nanosheets.

scholarly journals Synthesis of few-layer 2H-MoSe2 thin films with wafer-level homogeneity for high-performance photodetector

Nanophotonics ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 1959-1969 ◽  
Author(s):  
Tian-Jun Dai ◽  
Yu-Chen Liu ◽  
Xu-Dong Fan ◽  
Xing-Zhao Liu ◽  
Dan Xie ◽  
...  
Keyword(s):  
Thin Films ◽  
High Performance ◽  
Deep Understanding ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
Fast Response ◽  
Wafer Level ◽  
Large Area ◽  
Carrier Recombination ◽  
Layer Deposition

AbstractThe unique structural and physical properties of two-dimensional (2D) atomic layer semiconductors render them promising candidates for electronic or optoelectronic devices. However, the lack of efficient and stable approaches to synthesize large-area thin films with excellent uniformity hinders their realistic applications. In this work, we reported a method involving atomic layer deposition and a chemical vapor deposition chamber to produce few-layer 2H-MoSe2 thin films with wafer-level uniformity. The reduction of MoO3 was found indispensable for the successful synthesis of MoSe2 films due to the low vaporization temperature. Moreover, a metal-semiconductor-metal photodetector (PD) was fabricated and investigated systematically. We extracted an ultrahigh photoresponsivity approaching 101 A/W with concomitantly high external quantum efficiency up to 19,668% due to the produced gain arising from the holes trapped at the metal/MoSe2 interface, the band tail state contribution, and the photogating effect. A fast response time of 22 ms was observed and attributed to effective nonequilibrium carrier recombination. Additionally, the ultrahigh photoresponsivity and low dark current that originated from Schottky barrier resulted in a record-high specific detectivity of up to 2×1013 Jones for 2D MoSe2/MoS2 PDs. Our findings revealed a pathway for the development of high-performance PDs based on 2D MoSe2 that are inexpensive, large area, and suitable for mass production and contribute to a deep understanding of the photoconductivity mechanisms in atomically thin MoSe2. We anticipate that these results are generalizable to other layer semiconductors as well.

scholarly journals A Novel Carbon-Assisted Chemical Vapor Deposition Growth of Large-Area Uniform Monolayer MoS2 and WS2

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2423
Author(s):  
Jeonghwan Bae ◽  
Youngdong Yoo
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Carbon Powder ◽  
Carbon Cloth ◽  
Monolayer Mos2 ◽  
Large Area ◽  
High Quality ◽  
Chemical Vapor Deposition Growth ◽  
Cvd Method

Monolayer MoS2 can be used for various applications such as flexible optoelectronics and electronics due to its exceptional optical and electronic properties. For these applications, large-area synthesis of high-quality monolayer MoS2 is highly desirable. However, the conventional chemical vapor deposition (CVD) method using MoO3 and S powder has shown limitations in synthesizing high-quality monolayer MoS2 over a large area on a substrate. In this study, we present a novel carbon cloth-assisted CVD method for large-area uniform synthesis of high-quality monolayer MoS2. While the conventional CVD method produces thick MoS2 films in the center of the substrate and forms MoS2 monolayers at the edge of the thick MoS2 films, our carbon cloth-assisted CVD method uniformly grows high-quality monolayer MoS2 in the center of the substrate. The as-synthesized monolayer MoS2 was characterized in detail by Raman/photoluminescence spectroscopy, atomic force microscopy, and transmission electron microscopy. We reveal the growth process of monolayer MoS2 initiated from MoS2 seeds by synthesizing monolayer MoS2 with varying reaction times. In addition, we show that the CVD method employing carbon powder also produces uniform monolayer MoS2 without forming thick MoS2 films in the center of the substrate. This confirms that the large-area growth of monolayer MoS2 using the carbon cloth-assisted CVD method is mainly due to reducing properties of the carbon material, rather than the effect of covering the carbon cloth. Furthermore, we demonstrate that our carbon cloth-assisted CVD method is generally applicable to large-area uniform synthesis of other monolayer transition metal dichalcogenides, including monolayer WS2.

scholarly journals Large-area growth of SnS2 nanosheets by chemical vapor deposition for high-performance photodetectors

RSC Advances ◽  
2021 ◽  
Vol 11 (48) ◽  
pp. 29960-29964
Author(s):  
Ying Chen ◽  
Man Zhang
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
High Performance ◽  
Chemical Vapor ◽  
Large Area ◽  
Si Substrates ◽  
Cvd Method ◽  
Area Growth

Large-area SnS2 nanosheets were grown through a CVD method by using SnCl2 on SiO2/Si substrates as the precursors. The SnS2 nanosheets-based photodetectors shown high-performance.

High quality and high performance adsorption of Congo red using as-grown MWCNTs synthesized over a Co-MOF as a catalyst precursor via the CVD method

2017 ◽  
Vol 46 (48) ◽  
pp. 17067-17073 ◽  
Author(s):  
Hong-Yan Lin ◽  
Jing Zhao ◽  
Ge Song ◽  
Jian Luan ◽  
Xiang-Xiang Liu ◽  
...  
Keyword(s):  
Congo Red ◽  
High Performance ◽  
Catalyst Precursor ◽  
High Quality ◽  
Cvd Method

A Co-MOF has been synthesized and characterized, which was firstly used as a combined catalyst precursor to synthesize MWCNTs with high performance in the adsorption of CR.

High Quality Amorphous Silicon Prepared by Catalytic Chemical Vapor Deposition (CTL-CVD) Method

1987 ◽  
Vol 95 ◽  
Author(s):  
Hideki Matsumura
Keyword(s):  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Optical Band Gap ◽  
Chemical Vapor ◽  
Catalytic Reactions ◽  
Gas Mixture ◽  
High Quality ◽  
Phosphorus Doping ◽  
Cvd Method ◽  
Hydrogenated Amorphous

AbstractA new method of producing high quality hydrogenated amorphous silicon (a-Si:H) and its compound films is presented. An SiH4 and H2 gas mixture is decomposed without using any plasmas or photochemical excitation, but using only thermal and catalytic reactions between deposition gas and a heated tungsten catalyzer. Photoconductivity of a-Si:H films produced by, this method reaches 10−3 (Ωcm)−1 and photosensitivity exceeds 105 for illumination of AM-1 light of 100 mW/cm2, highly efficient boron- or phosphorus-doping into the films is achieved, and also the optical band gap of the films is easily controlled without apparent degradation of the properties by adding GeH4 gas to the deposition gas.

scholarly journals Growth of Pseudomorphic GeSn at Low Pressure with Sn Composition of 16.7%

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7637
Author(s):  
Joshua Grant ◽  
Grey Abernathy ◽  
Oluwatobi Olorunsola ◽  
Solomon Ojo ◽  
Sylvester Amoah ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
High Performance ◽  
Chemical Vapor ◽  
Low Pressure ◽  
Great Promise ◽  
High Quality ◽  
Reactor Material ◽  
Monolithically Integrated ◽  
Vapor Deposition Technique

Group-IV alloy GeSn holds great promise for the high-performance optoelectronic devices that can be monolithically integrated on Si for near- and mid-infrared applications. Growth of GeSn using chemical vapor deposition technique with various Sn and Ge precursors has been investigated worldwide. To achieve relatively high Sn incorporation, the use of higher pressure and/or higher order Ge hydrides precursors were reported. In this work, we successfully demonstrated the growth of high-quality GeSn with Sn composition of 16.7% at low pressure of 12 Torr. The alloy was grown using the commercially available GeH4 and SnCl4 precursors via a chemical vapor deposition reactor. Material and optical characterizations were performed to confirm the Sn incorporation and to study the optical properties. The demonstrated growth results reveal a low-pressure growth window to achieve high-quality and high Sn alloys for future device applications.

scholarly journals HIGH PERFORMANCE COMPUTING FOR DSM EXTRACTION FROM ZY-3 TRI-STEREO IMAGERY

2016 ◽  
Vol III-1 ◽  
pp. 113-120
Author(s):  
Shuning Lu ◽  
Shicun Huang ◽  
Zhiqiang Pan ◽  
Huawu Deng ◽  
David Stanley ◽  
...  
Keyword(s):  
High Performance Computing ◽  
High Performance ◽  
Bundle Adjustment ◽  
Surface Model ◽  
Stereo Pair ◽  
Large Area ◽  
High Quality ◽  
Efficient Manner ◽  
Stereo Imagery ◽  
Performance Computing

ZY-3 has been acquiring high quality imagery since its launch in 2012 and its tri-stereo (three-view or three-line-array) imagery has become one of the top choices for extracting DSM (Digital Surface Model) products in China over the past few years. The ZY-3 tri-stereo sensors offer users the ability to capture imagery over large regions including an entire territory of a country, such as China, resulting in a large volume of ZY-3 tri-stereo scenes which require timely (e.g., near real time) processing, something that is not currently possible using traditional photogrammetry workstations. This paper presents a high performance computing solution which can efficiently and automatically extract DSM products from ZY-3 tri-stereo imagery. The high performance computing solution leverages certain parallel computing technologies to accelerate computation within an individual scene and then deploys a distributed computing technology to increase the overall data throughput in a robust and efficient manner. By taking advantage of the inherent efficiencies within the high performance computing environment, the DSM extraction process can exploit all combinations offered from a set of tri-stereo images (forward-backword, forward-nadir and backword-nadir). The DSM results merged from all of the potential combinations can minimize blunders (e.g., incorrect matches) and also offer the ability to remove potential occlusions which may exist in a single stereo pair, resulting in improved accuracy and quality versus those that are not merged. Accelerated performance is inherent within each of the individual steps of the DSM extraction workflow, including the collection of ground control points and tie points, image bundle adjustment, the creation of epipolar images, and computing elevations. Preliminary experiments over a large area in China have proven that the high performance computing system can generate high quality and accurate DSM products in a rapid manner.

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