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Thin film Sn2S3 via chemical deposition and controlled heating - its prospects as a solar cell absorber
摘要： As a semiconductor of “earth-abundant” elements, Sn2S3 with a bandgap (Eg) close to 1 eV merits attention, but a method to prepare phase-pure thin film remains elusive. We report the formation of Sn2S3 thin film of 360 nm in thickness by heating chemically deposited tin sulfide thin films at 450 oC during 30 – 45 min in presence of sulfur at a pressure, 75 Torr of nitrogen. Energy dispersive x-ray emission spectra and grazing incidence x-ray diffraction established a reaction route for this conversion of SnS completely to Sn2S3 via an intermediate phase, SnS2. The optical bandgap of the material is 1.25 eV (indirect) and 1.75 eV (direct, forbidden). The optical absorption suggests a light-generated current density of 30 mA/cm2 for the Sn2S3 film (360 nm) as a solar cell absorber. Thin film Sn2S3 formed in 30 min heating has a p-type electrical conductivity in the dark of 1x10–4 Ω–1 cm–1, which increases to 3x10–4 Ω–1 cm–1 in 0.2 s under 800 W/m2 tungsten-halogen illumination. An estimate made for its mobility-lifetime product is, 6x10–6 cm2 V–1. We discuss the prospects of this material for solar cells.
关键词： SnS-CUB,Sn2S3,semiconductor thin film,chemical deposition,energy conversion,ottemannite,cubic tin sulfide,renewable energy,optical and electrical properties,solar cells
更新于2025-09-11 14:15:04
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Organic LED based light sensor for detection of ovarian cancer
摘要： Organic devices possess an interdisciplinary facet that can be utilized in the different fields; communication, memory devices, bio-degradable technology and sensor application owing to their robustness, light weight and low power requirements. The proposed work is focused on the development of a sensor application based on the organic LEDs for the diagnosis of ‘Ovarian Cancer’. Two organic LEDs: Multilayered OLED and triple hole block layer OLED are analyzed for utilization as light detector and light source in the sensing device for cancer detection. Multilayered OLED depicts excellent light detection qualities owing to lower electron hole recombination and it is six times better as compared to the triple hole block layer OLED. Therefore, it is used as the detector element in the sensing device. On the other hand, triple hole block layer OLED, is used as light source due to its high luminescence characteristics of 25,285 cd/m2. Further, a dual gate OTFT is used to drive the triple hole block layer OLED, which is utilized as the light source. DG OTFT in dual gate mode is 18% better compared to single gate mode. Thus DG-OTFT in dual gate mode is able to generate 18 volts at the terminals of the triple HBL OLED necessary for its operation. Thereafter, light detection is performed utilizing the OLED. Multilayered OLED depicted excellent light detecting capabilities. It is able to generate a cathode current of 29mA and 13mA at an incident wavelength of 420 and 440 nm, respectively, an essential requirement for present sensor application. Therefore, it presents a possibility to fabricate a portable fully flexible device for the screening and diagnosis of the ovarian cancer.
关键词： Ovarian Cancer,Triple Hole Block Layer (THBL) OLED,Dual Gate-Organic Thin Film Transistor (DG-OTFT),Bio-Medical Sensor,Organic Light Emitting Diode (OLED)
更新于2025-09-11 14:15:04
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Fabrication of Sb2Se3 thin film solar cells by co-sputtering of Sb2Se3 and Se targets
摘要： Antimony selenide (Sb2Se3) has attracted scientific interest due to its many advantages such as its appropriate band gap, non-toxicity, element abundance, and high absorption coefficient (> 105 cm?1). However, selenium (Se) is easily lost at high vapor pressures, thus leading to Se vacancies and increased recombination centers in films. In this work, Sb2Se3 films with good crystallinity were fabricated by co-sputtering of Sb2Se3 and Se targets with a substrate temperature of 350 °C and without a subsequent annealing process. The crystal structural properties, surface morphology, and optical and electrical properties of films with different Se contents were explored. Finally, we fabricated solar cells with a structure of FTO/CdS/Sb2Se3/Au and achieved an efficiency up to 3.47%.
关键词： Thin film,Selenium supplement,Co-sputtering,Sb2Se3
更新于2025-09-11 14:15:04
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European Microscopy Congress 2016: Proceedings || Electron holography by means of tilted reference waves
摘要： The paper discusses the direct recognition of the phase of light waves by means of a thin-film interference filter. It explores the experimental realization of a reference wave and a plane reference wave to form an interference pattern at the detector plane. The experimental setup includes a laser source, a beam splitter, and a detector array. The results demonstrate the feasibility of direct phase recognition with high spatial resolution.
关键词： light waves,spatial resolution,interference pattern,thin-film interference,phase recognition
更新于2025-09-11 14:15:04
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MoS2 hybrid heterostructure thin film decorated with CdTe quantum dots for room temperature NO2 gas sensor
摘要： MoS2 hybrid heterostructure thin film decorated with CdTe quantum dots for room temperature NO2 gas sensor
关键词： Hybrid heterostructure,Sputtering,NO2 gas sensor,CdTe/MoS2 thin film
更新于2025-09-11 14:15:04
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High efficient photovoltaics in BaTiO<sub>3</sub> thin film
摘要： BaTiO3 thin film was grown on a n-type silicon (100) single crystal substrate by high vacuum magnetron sputtering. The samples were annealed under vacuum conditions at 400, 500 and 600°C, respectively. The photovoltaic effect in BaTiO3 thin film was observed, and a high power conversion efficiency of 1.25% was achieved. In addition, the short circuit current density of 134μA/cm2 under white light illumination was obtained in the BaTiO3 thin film. Besides, the current ratio of light ON/OFF state is about 100 at 2v bias. Our experiments suggest that BaTiO3 thin film possesses the potential photovoltaic application in future.
关键词： photovoltaic effect,BaTiO3 thin film,power conversion efficiency
更新于2025-09-11 14:15:04
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Dynamics Contributions to the Growth Mechanism of Ga2O3 Thin Film and NWs Enabled by Ag Catalyst
摘要： In the last few years, interest in the use of gallium oxide (Ga2O3) as a semiconductor for high power/high temperature devices and UV nano-sensors has grown. Ga2O3 has an enormous band gap of 4.8 eV, which makes it well suited for applications in harsh environments. In this work, we explored the effect of Ag thin film as a catalyst to grow gallium oxide. The growth of gallium oxide thin film and nanowires can be achieved by heating and oxidizing pure gallium at high temperatures (~1000 °C) in the presence of trace amounts of oxygen. We present the results of structural, morphological, and elemental characterization of the β-Ga2O3 thin film and nanowires. In addition, we explore and compare the sensing properties of the β-Ga2O3 thin film and nanowires for UV detection. The proposed process can be optimized to a high scale production Ga2O3 nanocrystalline thin film and nanowires. By using Ag thin film as a catalyst, we can control the growth parameters to obtain either nanocrystalline thin film or nanowires.
关键词： Ga2O3,thermal oxidation,nanowires,thin film,silver catalyst,quartz
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Direct Laser Synthesis of Two-Dimensional Transition Metal Dichalcogenides
摘要： The emergence of nanomaterials with their often superior mechanical, electronic and optical properties compared with bulk form demands a robust technology that can synthesize, modify and pattern scalably and cost effectively. This can be fulfilled via laser processing protocols which produce such materials with both high precision and excellent spatial controllability [1]. Direct laser synthesis of nanomaterials such as graphene and nano-structured metal oxides have been explored thoroughly for a wide range of applications [2,3]. However, to date, there are only a few reports associated with the laser processing of two-dimensional transition metal dichalcogenides (2D-TMDCs) [4]. These mainly utilize laser radiation for thinning TMDC films through sublimation down to a single molecular thickness [1]. However, this top-down approach is not practical for large- area and scalable production. In addition, further processing steps such as lithographic patterning are then required for discrete device fabrication. Here we present a novel method for the local synthesis and patterning of two-dimensional MoS2 and WS2 layers. The synthesis of these materials is achieved by spatially selective, visible laser irradiation of suitable precursors coated on the surface of planar substrates under ambient, room temperature conditions. The non- exposed precursor regions are then completely removed in a single step, revealing the synthesised 2D-TMDCs. This method can produce micro-patterned films with lateral dimensions that approach the diffraction limit of the focused laser beam. An example of such laser synthesised MoS2 tracks can be seen in the optical microscopy image of Figure 1(a) where it clearly shows a well-defined micro-pattern without any precursor residue. Using this method, we have achieved local synthesis of of MoS2 and WS2 with thickness down to three molecular layers for MoS2 and monolayer WS2 on various glass and crystalline substrates. The quality and thickness of the resulting films can be tuned by modifying the precursor chemistry and laser parameters. Different microprobe and spectroscopic spectroscopy, photoluminescence spectroscopy (PL) and X-ray photoelectron spectroscopy (XPS) have been used to assess the quality and thickness of the deposited MoS2 and WS2 structures. Finally, we have demonstrated the electronic functionality of our films by fabricating a thin film transistor (TFT). The transfer characteristics (source-drain current vs gate voltage) of such a TFT using a laser-synthesised MoS2 channel is shown in Figure 1(b).
关键词： Two-Dimensional Transition Metal Dichalcogenides,WS2,MoS2,Direct Laser Synthesis,Thin Film Transistor
更新于2025-09-11 14:15:04
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Layer-by-layer assembly of polyelectrolytes-wrapped multi-walled carbon nanotubes on long period fiber grating sensors
摘要： A new type of long period fiber grating (LPG) sensor coated with polyelectrolytes-wrapped multi-walled carbon nanotube (MWCNT) (PE-CNT) thin film is reported in this study. The novel morphologies of the MWCNT-based nanostructured thin film are observed by scanning electron microscopy characterization. The refractive index and pH sensing behaviors of LPGs with pure (PE)10 thin film and with (PE-CNT)10 thin film, respectively are compared. Results show that for LPG with (PE-CNT)10 thin film the transmission intensity at the resonance wavelength decreases noticeably with the increase of the surrounding refractive index. This is distinct from the sensing mechanism of LPG with (PE)10 thin film, which is based on the resonance wavelength shift. The LPG with a (PE-CNT)10 thin film provides enhanced pH sensitivity compared with that of a (PE)10 thin film. The LPG with (PE-CNT)10 thin film has a fast response rate and a good repeatability, thus demonstrating its strong potentiality for practical monitoring applications.
关键词： layer-by-layer assembly,sensor,thin film,Long period fiber grating,pH sensing,carbon nanotube
更新于2025-09-11 14:15:04
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Physics of Energy Conversion () || 10. Photovoltaic energy conversion
摘要： In a photovoltaic device, solar energy is converted into electricity along a path very different from the one taken in a solarthermal power plant. Here, in a first step the energy of the solar photons is converted into chemical energy in a solid state absorber. This means that the absorber is brought into an electronically excited state involving a reconfiguration of its charge carriers by the generation of electron/hole (e?/h+)-pairs, i.e. by the following reaction: Ground state + ?? → e? + h+. Here, ?? represents a photon with sufficient energy to bring an electron to the excited state. The chemical energy of the charge carrier ensembles in the conduction and valence bands is then converted into electrical energy by spatially separating the e?/h+-pairs via electrical contacts of the absorber which are electron or hole selective, respectively. In general such selective contacts can only be realized by a jump in the material properties between the two contacts, an example for this being a pn-junction. Since under illumination electrons and holes have different electrochemical potentials in the absorber material, this separation leads to a voltage drop between the contacts selective for the different charge carrier types. It is thus the selectivity of the contacts that introduces the built-in asymmetry into the solar cell, making it a usable voltage source (see Section 5.2). This basic working principle is true for all types of solar cells, ranging from conventional solar cells built from crystalline silicon (c-Si) over thin film solar cells fabricated from different materials such as, e.g. Cu(In,Ga)Se2 (CIGS) to organic or dye sensitized solar cells, and is schematically shown in Figure 10.1.
关键词： electricity,solid state absorber,solar energy,photovoltaic,pn-junction,dye sensitized solar cells,organic solar cells,CIGS,thin film solar cells,crystalline silicon,electron/hole pairs
更新于2025-09-11 14:15:04