scholarly journals Fabrication and Characterization of Near Infrared Molybdenum Disulfide/Silicon Heterojunction Photodetector by Drop Casting Method

2021 ◽  
Author(s):  
Haroon Rashid ◽  
Norhana Arsad ◽  
Harith Ahmad ◽  
Ahmad Ashrif A. Bakar ◽  
Mamun Ibne Reaz
Keyword(s):  
Molybdenum Disulfide ◽  
Near Infrared ◽  
Film Growth ◽  
Low Cost ◽  
Incident Light ◽  
Cost Effective ◽  
Optoelectronic Device ◽  
Casting Method ◽  
Incident Laser Power ◽  
Device Applications

In this work, a highly efficient, molybdenum disulfide (MoS2) based near infrared (NIR) heterojunction photodetector is fabricated on a Si substrate using a cost-effective and simple drop casting method. A non-stoichiometric and inhomogeneous MoS2 layer with a S/Mo ratio of 2.02 is detected using energy dispersive X-ray spectroscopy and field emission scanning electron microscope analysis. Raman shifts are noticed at 382.42 cm-1 and 407.97 cm-1, validating MoS2 thin film growth with a direct bandgap of 2.01 eV. The fabricated n-MoS2/p-Si photodetector is illuminated with a 785 nm laser at different intensities, and demonstrate the ability of the photodetector to work in both regions, the forward biased and reverse biased from above 1.5 V and less than -1.0 V. The highest responsivity, R is calculated to be 0.52 A/W while the detectivity D* is 4.08 x 10^10 Jones for an incident light intensity of 9.57 mW/cm2. The minimum rise and fall times are calculated as 1.77 ms and 1.31 ms for an incident laser power of 9.57 mW/cm^2 and 6.99 mW/cm^2 respectively at a direct current bias voltage of 10 V. The demonstrated results are promising for the low-cost fabrication of a thin MoS2 film for photonics and optoelectronic device applications.

Discotic columnar liquid-crystalline polymer semiconducting materials with high charge-carrier mobility via rational macromolecular engineering

2017 ◽  
Vol 8 (21) ◽  
pp. 3286-3293 ◽  
Author(s):  
Bin Mu ◽  
Xingtian Hao ◽  
Jian Chen ◽  
Qian Li ◽  
Chunxiu Zhang ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Cost Effective ◽  
Crystalline Polymer ◽  
Charge Carrier Mobility ◽  
Optoelectronic Device ◽  
Side Chain ◽  
Liquid Crystal Polymers ◽  
Semiconducting Materials ◽  
Organic Semiconducting Materials ◽  
Device Applications

Well-prepared side-chain discotic liquid crystal polymers with shorter spacers in ordered columnar phases are fascinating and promising cost-effective, solution-processable organic semiconducting materials for various potential optoelectronic device applications.

scholarly journals 2D MoS2 Encapsulated Silicon Nanopillar Array with High-Performance Light Trapping Obtained by Direct CVD Process

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 267
Author(s):  
Minyu Bai ◽  
Zhuoman Wang ◽  
Jijie Zhao ◽  
Shuai Wen ◽  
Peiru Zhang ◽  
...  
Keyword(s):  
Silicon Substrate ◽  
High Performance ◽  
Low Cost ◽  
Light Trapping ◽  
Incident Light ◽  
Single Layer ◽  
Chemical Vapor ◽  
Optoelectronic Device ◽  
Planar Silicon ◽  
Shortwave Infrared

Weak absorption remains a vital factor that limits the application of two-dimensional (2D) materials due to the atomic thickness of those materials. In this work, a direct chemical vapor deposition (CVD) process was applied to achieve 2D MoS2 encapsulation onto the silicon nanopillar array substrate (NPAS). Single-layer 2D MoS2 monocrystal sheets were obtained, and the percentage of the encapsulated surface of NPAS was up to 80%. The reflection and transmittance of incident light of our 2D MoS2-encapsulated silicon substrate within visible to shortwave infrared were significantly reduced compared with the counterpart planar silicon substrate, leading to effective light trapping in NPAS. The proposed method provides a method of conformal deposition upon NPAS that combines the advantages of both 2D MoS2 and its substrate. Furthermore, the method is feasible and low-cost, providing a promising process for high-performance optoelectronic device development.

scholarly journals III–V Nanowires: Synthesis, Property Manipulations, and Device Applications

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Ming Fang ◽  
Ning Han ◽  
Fengyun Wang ◽  
Zai-xing Yang ◽  
SenPo Yip ◽  
...  
Keyword(s):  
High Performance ◽  
Low Cost ◽  
Volume Ratio ◽  
Chemical Vapor ◽  
Cost Effective ◽  
Research Field ◽  
Synthesis Methods ◽  
Comprehensive Overview ◽  
Device Applications ◽  
Property Control

III–V semiconductor nanowire (NW) materials possess a combination of fascinating properties, including their tunable direct bandgap, high carrier mobility, excellent mechanical flexibility, and extraordinarily large surface-to-volume ratio, making them superior candidates for next generation electronics, photonics, and sensors, even possibly on flexible substrates. Understanding the synthesis, property manipulation, and device integration of these III–V NW materials is therefore crucial for their practical implementations. In this review, we present a comprehensive overview of the recent development in III–V NWs with the focus on their cost-effective synthesis, corresponding property control, and the relevant low-operating-power device applications. We will first introduce the synthesis methods and growth mechanisms of III–V NWs, emphasizing the low-cost solid-source chemical vapor deposition (SSCVD) technique, and then discuss the physical properties of III–V NWs with special attention on their dependences on several typical factors including the choice of catalysts, NW diameters, surface roughness, and surface decorations. After that, we present several different examples in the area of high-performance photovoltaics and low-power electronic circuit prototypes to further demonstrate the potential applications of these NW materials. Towards the end, we also make some remarks on the progress made and challenges remaining in the III–V NW research field.

Synthetic Route of CdSe Nanocrystalline Films Fabricated by Substrate Vibration Assisted Drop Casting Method

2020 ◽  
Vol 12 (6) ◽  
pp. 761-770
Author(s):  
Megha Sachdeva ◽  
P. Agrawal ◽  
Sheenam Sachdeva ◽  
K. K. Bhasin ◽  
S. K. Tripathi ◽  
...  
Keyword(s):  
Low Cost ◽  
Cost Effective ◽  
Cdse Nanocrystals ◽  
Nanocrystalline Films ◽  
X Ray Diffraction ◽  
Casting Method ◽  
Substrate Vibration ◽  
Ultrasonic Substrate Vibration ◽  
Particle Size Analyzer ◽  
Average Size

Herein, we report a greener, non-toxic, cost effective and a modest scheme for the fabrication of excellent CdSe nanocrystals (NCs). Precursors for the present reaction are synthesized by the treatment of cadmium chloride (CdCl2) with 2-pyridyl selenolate (NaSeC5H4N) resulting a complex of the formula [(C5H4NSe)2Cd]. The complex is characterized by NMR (1H and 13C) and IR spectroscopies. The complex, [(C5H4NSe)2Cd] is found to be polymeric in nature, as indicated by its insolubility in solvents, and is further customized as a single-source pioneers for the preparation of colloidal CdSe NCs. Thermolysis of [(C5H4NSe)2 Cd] has been successfully carried out by hotinjection method using low-cost and harmless oleic acid (OA) as the coordinating solvent, thereby rejecting the need of air-sensitive and toxic solvents. Based upon dynamic light scattering (DLS) technique, the average size of colloidal CdSe NCs are determined using particle size analyzer. The average size of colloidal NCs comes out to be 6.3 nm. Thin films of colloidal CdSe NCs are deposited on glass substrate using drop-casting (DC) and ultrasonic substrate vibration assisted drop casting (SVADC) methods to study their use as workable materials for engineering devices. The films are characterized by ultraviolet-visible spectroscopy (UV-vis), photoluminescence (PL) studies, X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques.

scholarly journals A Cost-Effective and Portable Optical Sensor System to Estimate Leaf Nitrogen and Water Contents in Crops

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1449 ◽  
Author(s):  
Mohammad Habibullah ◽  
Mohammad Reza Mohebian ◽  
Raju Soolanayakanahally ◽  
Khan A. Wahid ◽  
Anh Dinh
Keyword(s):  
Water Content ◽  
Near Infrared ◽  
Low Cost ◽  
Gaussian Process Regression ◽  
Cost Effective ◽  
Leaf Nitrogen ◽  
Sensor System ◽  
Coefficient Of Determination ◽  
Healthy Growth ◽  
Water Contents

Non-invasive determination of leaf nitrogen (N) and water contents is essential for ensuring the healthy growth of the plants. However, most of the existing methods to measure them are expensive. In this paper, a low-cost, portable multispectral sensor system is proposed to determine N and water contents in the leaves, non-invasively. Four different species of plants—canola, corn, soybean, and wheat—are used as test plants to investigate the utility of the proposed device. The sensor system comprises two multispectral sensors, visible (VIS) and near-infrared (NIR), detecting reflectance at 12 wavelengths (six from each sensor). Two separate experiments were performed in a controlled greenhouse environment, including N and water experiments. Spectral data were collected from 307 leaves (121 for N and 186 for water experiment), and the rational quadratic Gaussian process regression (GPR) algorithm was applied to correlate the reflectance data with actual N and water content. By performing five-fold cross-validation, the N estimation showed a coefficient of determination ( R 2 ) of 63.91% for canola, 80.05% for corn, 82.29% for soybean, and 63.21% for wheat. For water content estimation, canola showed an R 2 of 18.02%, corn showed an R 2 of 68.41%, soybean showed an R 2 of 46.38%, and wheat showed an R 2 of 64.58%. The result reveals that the proposed low-cost sensor with an appropriate regression model can be used to determine N content. However, further investigation is needed to improve the water estimation results using the proposed device.

Pendeo Epitaxy Of 3C-SiC on Si Substrates

2000 ◽  
Vol 622 ◽  
Author(s):  
G.E. Carter ◽  
T. Zheleva ◽  
G. Melnychuck ◽  
B. Geil ◽  
K. Jones ◽  
...  
Keyword(s):  
Low Cost ◽  
Large Diameter ◽  
Side Wall ◽  
Cost Effective ◽  
Interface Layer ◽  
Lateral Epitaxial Overgrowth ◽  
Si Substrates ◽  
Device Applications ◽  
Sic Film

ABSTRACTPendeo Epitaxy is a type of Lateral Epitaxial Overgrowth (LEO) that instead of using a dielectric buffer layer, uses an etched substrate to grow laterally without an interface layer. We report the first successful growth of 3C-SiC on Si using Pendeo epitaxy. Rectangular stripes of 3C-SiC on (100) Si substrates were fabricated, along both the [110] and [100] directions. Pendeo epi was only observed for columns parallel to [001], indicating a preferred growth facet for Pendeo epi of 3C-SiC on Si. SEM and TEM investigations were performed to assess the material quality of the Pendeo 3C-SiC material. Films were grown for 60 min at 1310°C and film coalescence was achieved without evidence of voids where the growth fronts joined. TEM data indicate not only the growth of vertical and lateral 3C-SiC on the 3C-SiC seed layer but direct nucleation of 3C-SiC on the exposed Si columns side wall and trench bottom, despite the lack of a carbonization procedure. The quality of the Pendeo 3C-SiC film appears to be of high quality indicating that Pendeo epi of 3C-SiC on low-cost, large-diameter Si substrates may prove to be a cost effective way to grow device-grade SiC layers on Si substrates for device applications.

scholarly journals Effect of Precursors on Structural and Optical Properties of Sol-Gel Synthesized ZnO Nanopowders

2019 ◽  
Vol 31 (8) ◽  
pp. 1825-1829
Author(s):  
A. Vanaja ◽  
Jaison Jeevanandam ◽  
M. Suresh
Keyword(s):  
Zinc Oxide ◽  
Optical Properties ◽  
Optical Absorption ◽  
Sol Gel ◽  
Cost Effective ◽  
Optoelectronic Device ◽  
Zinc Nitrate ◽  
X Ray Diffraction ◽  
Absorption And Emission ◽  
Device Applications

The present work aims at evaluating the outcome of zinc precursors on the crystal structure, shape, surface and optical properties of ZnO nanopowders. Zinc oxide nanopowders are fabricated via simple, cost-effective, low-temperature, the sol-gel method using different zinc precursors such as zinc nitrate and zinc chloride. The structural properties of the obtained ZnO nanopowders are studied using X-ray diffraction spectra and their morphology from SEM micrographs. Further, Fourier transform infrared spectra reveals the existence of functional groups that supports the formation of zinc oxide. Moreover, optical absorption and emission of ZnO nanopowders were evaluate during ultraviolet-visible and photoluminescence spectra. The results of this study revealed that the precursor is significant in altering the crystallite size, shape, optical absorption and emission entities of nanopowders. In addition, the role of zinc precursors to fabricate nanopowders that is suitable for various optoelectronic device applications were also discussed.

scholarly journals Vein Pattern Locating Technology for Cannulation: A Review of the Low-Cost Vein Finder Prototypes Utilizing near Infrared (NIR) Light to Improve Peripheral Subcutaneous Vein Selection for Phlebotomy

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3573 ◽  
Author(s):  
Cheng-Tang Pan ◽  
Mark D. Francisco ◽  
Chung-Kun Yen ◽  
Shao-Yu Wang ◽  
Yow-Ling Shiue
Keyword(s):  
Near Infrared ◽  
Infrared Imaging ◽  
Low Cost ◽  
Venous Blood ◽  
Cost Effective ◽  
Medical Laboratory ◽  
Scientific Publications ◽  
Medical Practitioners ◽  
Nir Light ◽  
Number Of Patients

One of the most common means for diagnosis is through medical laboratory testing, which primarily uses venous blood as a sample. This requires an invasive method by cannulation that needs proper vein selection. The use of a vein finder would help the phlebotomist to easily locate the vein, preventing possible pre-analytical error in the specimen collection and even more discomfort and pain to the patient. This paper is a review of the scientific publications on the different developed low-cost vein finder prototypes utilizing camera assisted near infrared (NIR) light technology. Methods: Electronic databases were searched online, these included PubMed (PMC), MEDLINE, Science Direct, ResearchGate, and Institute of Electrical and Electronics Engineers (IEEE) Xplore digital library. Specifically, publications with the terms vein finder prototype, NIR technology, vein detection, and infrared imaging were screened. In addition, reference lists were used to further review related publications. Results: Cannulation challenges medical practitioners because of the different factors that can be reduced by the utilization of a vein finder. A limited number of publications regarding the assessment of personnel performing cannulation were observed. Moreover, variations in methodology, number of patients, type of patients according to their demographics and materials used in the assessment of the developed prototypes were noted. Some studies were limited with regard to the actual human testing of the prototype. Conclusions: The development of a low-cost effective near infrared (NIR) vein finder remains in the phase of improvement. Since, it is being challenged by different human factors, increasing the number of parameters and participants/human for actual testing of the prototypes must also be taken into consideration for possible commercialization. Finally, it was noted that publications regarding the assessment of the performance of phlebotomists using vein finders were limited.

scholarly journals Luminescent κ-Carrageenan-Based Electrolytes Containing Neodymium Triflate

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1020 ◽  
Author(s):  
S. Nunes ◽  
S. Saraiva ◽  
R. Pereira ◽  
M. Silva ◽  
L. Carlos ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Alkaline Earth ◽  
Near Infrared ◽  
Low Cost ◽  
Earth Metal ◽  
Cost Effective ◽  
Red Seaweeds ◽  
Multi Wavelength ◽  
Electrochemical Devices ◽  
Uv Visible

In recent years, the synthesis of polymer electrolyte systems derived from biopolymers for the development of sustainable green electrochemical devices has attracted great attention. Here electrolytes based on the red seaweeds-derived polysaccharide κ-carrageenan (κ-Cg) doped with neodymium triflate (NdTrif3) and glycerol (Gly) were obtained by means of a simple, clean, fast, and low-cost procedure. The aim was to produce near-infrared (NIR)-emitting materials with improved thermal and mechanical properties, and enhanced ionic conductivity. Cg has a particular interest, due to the fact that it is a renewable, cost-effective natural polymer and has the ability of gelling in the presence of certain alkali- and alkaline-earth metal cations, being good candidates as host matrices for accommodating guest cations. The as-synthesised κ-Cg-based membranes are semi-crystalline, reveal essentially a homogeneous texture, and exhibit ionic conductivity values 1–2 orders of magnitude higher than those of the κ-Cg matrix. A maximum ionic conductivity was achieved for 50 wt.% Gly/κ-Cg and 20 wt.% NdTrif3/κ-Cg (1.03 × 10−4, 3.03 × 10−4, and 1.69 × 10−4 S cm−1 at 30, 60, and 97 °C, respectively). The NdTrif-based κ-Cg membranes are multi-wavelength emitters from the ultraviolet (UV)/visible to the NIR regions, due to the κ-Cg intrinsic emission and to Nd3+, 4F3/2→4I11/2-9/2.

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