Phosphorene Oxide Quantum Dots Decorated ZnO Nanostructure-Based Hydrogen Gas Sensor
15 Mar 2021-IEEE Sensors Journal (Institute of Electrical and Electronics Engineers (IEEE))-Vol. 21, Iss: 6, pp 7283-7290
TL;DR: In this article, the decoration of Phosphorene oxide quantum dots (POQDs) on RF sputtered grown ZnO nanostructures for hydrogen gas sensing application was explored.
Abstract: Pristine ZnO based hydrogen sensors pose low sensitivity (~ 43%) at the operating temperature of 150°. Herein, we explore the decoration of Phosphorene oxide quantum dots (POQDs) on RF sputtered grown ZnO nanostructures for hydrogen gas sensing application. A simplistic approach such as drop cast method is employed to decorate electrosynthesized POQDs (2- $8~\mu \text{L}$ ) onto interdigitated electrodes over ZnO nanostructures. The suggested hydrogen sensor based on POQDs ( $6~\mu \text{L}$ )/ZnO nanostructures exhibits an outstanding sensing response (~70.6%) as compared to all the sensors for 100 ppm at 150°C. Enhanced sensing response from the POQDs( $6~\mu \text{L}$ )/ZnO nanostructure might be due to the enormous active surface area of POQDs (provides more active sites for hydrogen gas) and modulation of depletion region at the interface of POQDs and ZnO. The proposed sensor can be operated at mild temperature and consume low power which is the need of the hour for the hydrogen sensors for industrial applications.
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TL;DR: In this article , MoS2 structures with vertically aligned flower-like structure were synthesized using a simple hydrothermal technique and applied to the gate region of AlGaN/GaN HEMTs.
Abstract: The ability to monitor toxic gases under room-temperature conditions, with enhanced response and selectivity present in the atmosphere, is still considered as a technical challenge. In this context, we have fabricated AlGaN/GaN high electron mobility transistors (HEMTs) based sensors incorporating molybdenum disulphide (MoS2) functionalization for very sensitive, selective, and quick measurement of even trace amounts of hazardous NO2 gas in the ambient under room-temperature conditions. MoS2 structures with vertically aligned flower-like structure were synthesised using a simple hydrothermal technique and applied to the gate region of AlGaN/GaN HEMTs. The electrical characterisations of MoS2 functionalized AlGaN/GaN HEMTs are then used to detect the presence of NO2 gas. The fabricated sensor showed an enhanced relative sensing response in the range of 40.5–56.7% for 1–100 ppm NO2 gas with complete recovery to 1 ppm NO2 concentration under room-temperature conditions (25ᵒC) without applying any external thermal or optical stimuli. Furthermore, the cyclic and selectivity tests were performed and we found our sensor to be highly selective towards NO2 gas among various other gases. The experimental results showed that MoS2 had excellent properties for NO2 gas detection when used on such GaN-based sensing platform. These findings may be attributed to the exposed edge sites of MoS2 which compliment with configurations with sulphur and the chemisorption phenomenon on its surface that results in altering the drain to source current (IDS) of the HEMT at a constant drain to source voltage (VDS) of 0.5 V. These findings suggest that gas sensors based on the AlGaN/GaN HEMT structure appear to be a promising candidate for the advancement of application potentials of nitride-based integrated electronics.
8 citations
TL;DR: In this article , the electronic structure of phosphorene atomic chains (PACs) embedded in various dielectric environments is studied theoretically by using a configuration interaction approach beyond the conventional double-excitation scheme.
Abstract: The electronic structure of phosphorene atomic chains (PACs) embedded in various dielectric environments is studied theoretically by using a configuration interaction approach beyond the conventional double-excitation scheme. While the nominal single-particle gap of the PACs is shown to roughly obey an expected scaling law of ${L}^{\ensuremath{-}2}$, where $L$ measures the length of PACs, the quasiparticle shift is found to gradually converge to a value that is insensitive to the dielectric environment as $L$ increases. In the meantime, exciton binding energies are revealed to obey a simple scaling law of $0.96/(\ensuremath{\kappa}L)\ensuremath{-}0.02$, with $\ensuremath{\kappa}$ being the effective dielectric constant. As $L$ goes to infinity, the quasiparticle and excitonic effect are both found to be greatly suppressed as if the long-range electron-electron interactions are quenched in long PACs.
2 citations
TL;DR: In this paper , a self-aligned, cost-efficient, fully solution-processed, and low-voltage operated high-dimensional dielectric-based p-channel organic thin-film transistor (OTFT) has been developed and investigated for toxic ammonia analyte at room temperature (RT) 25 °C.
Abstract: In this article, a self-aligned, cost-efficient, fully solution-processed, and low-voltage operated high- ${k}$ dielectric-based p-channel organic thin-film transistor (OTFT) has been developed and investigated for toxic ammonia analyte at room temperature (RT—25 °C). A spin casting method has been utilized to deposit a high- ${k}$ dielectric, lanthanum zirconium oxide (LaZrOx), on a $\text{p}^{++}$ silicon substrate. The organic semiconductor channel deposition uses minimal wastage self-assembly floating film transfer method for poly(3-hexylthiophene-2,5-diyl) (P3HT) growth over hexamethyldisilazane (HMDS)-treated LaZrO $_{\textit {}x}$ dielectric. The doping of lanthanum in ZrOx material reduces the charge traps and rms surface roughness and also minimizes the other surface defects and carrier scattering at the dielectric interface. The solution-processed dielectric material is suitable for low-voltage operated OTFT due to its high capacitance per unit area of 486 nF/cm2 at 1 kHz and a low leakage current density of $\sim 0.5\times 10^{-{8}}$ A/cm2 at −2 V. Even at a low operating voltage of −2 V, the fabricated OTFT is capable of producing a good saturated current. The OTFT sensor results in a high response of 47% at 5 ppm NH3 analyte and a low detection limit of 11.65 ppb. The developed sensor exhibits a low average response and a recovery time of 9 and 50 s and is almost independent of relative humidity variations in the range of 30%–70%. The study reveals that this novel low-voltage OTFT device is capable of operating at −2 V and has shown a high sensitivity toward ammonia gas detection at RT.
2 citations
2 citations
DOI•
TL;DR: In this article, a self-aligned, cost-efficient, fully solution-processed, and low-voltage operated high dielectric-based p-channel organic thin-film transistor (OTFT) has been developed and investigated for toxic ammonia analyte at room temperature (RT-25 °C).
Abstract: In this article, a self-aligned, cost-efficient, fully solution-processed, and low-voltage operated high- ${k}$ dielectric-based p-channel organic thin-film transistor (OTFT) has been developed and investigated for toxic ammonia analyte at room temperature (RT—25 °C). A spin casting method has been utilized to deposit a high- ${k}$ dielectric, lanthanum zirconium oxide (LaZrOx), on a $\text{p}^{++}$ silicon substrate. The organic semiconductor channel deposition uses minimal wastage self-assembly floating film transfer method for poly(3-hexylthiophene-2,5-diyl) (P3HT) growth over hexamethyldisilazane (HMDS)-treated LaZrO $_{\textit {}x}$ dielectric. The doping of lanthanum in ZrOx material reduces the charge traps and rms surface roughness and also minimizes the other surface defects and carrier scattering at the dielectric interface. The solution-processed dielectric material is suitable for low-voltage operated OTFT due to its high capacitance per unit area of 486 nF/cm2 at 1 kHz and a low leakage current density of $\sim 0.5\times 10^{-{8}}$ A/cm2 at −2 V. Even at a low operating voltage of −2 V, the fabricated OTFT is capable of producing a good saturated current. The OTFT sensor results in a high response of 47% at 5 ppm NH3 analyte and a low detection limit of 11.65 ppb. The developed sensor exhibits a low average response and a recovery time of 9 and 50 s and is almost independent of relative humidity variations in the range of 30%–70%. The study reveals that this novel low-voltage OTFT device is capable of operating at −2 V and has shown a high sensitivity toward ammonia gas detection at RT.
1 citations
References
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TL;DR: The semiconductor ZnO has gained substantial interest in the research community in part because of its large exciton binding energy (60meV) which could lead to lasing action based on exciton recombination even above room temperature.
Abstract: The semiconductor ZnO has gained substantial interest in the research community in part because of its large exciton binding energy (60meV) which could lead to lasing action based on exciton recombination even above room temperature. Even though research focusing on ZnO goes back many decades, the renewed interest is fueled by availability of high-quality substrates and reports of p-type conduction and ferromagnetic behavior when doped with transitions metals, both of which remain controversial. It is this renewed interest in ZnO which forms the basis of this review. As mentioned already, ZnO is not new to the semiconductor field, with studies of its lattice parameter dating back to 1935 by Bunn [Proc. Phys. Soc. London 47, 836 (1935)], studies of its vibrational properties with Raman scattering in 1966 by Damen et al. [Phys. Rev. 142, 570 (1966)], detailed optical studies in 1954 by Mollwo [Z. Angew. Phys. 6, 257 (1954)], and its growth by chemical-vapor transport in 1970 by Galli and Coker [Appl. Phys. ...
10,260 citations
TL;DR: Recent developments in the search for innovative materials with high hydrogen-storage capacity are presented.
Abstract: Mobility — the transport of people and goods — is a socioeconomic reality that will surely increase in the coming years. It should be safe, economic and reasonably clean. Little energy needs to be expended to overcome potential energy changes, but a great deal is lost through friction (for cars about 10 kWh per 100 km) and low-efficiency energy conversion. Vehicles can be run either by connecting them to a continuous supply of energy or by storing energy on board. Hydrogen would be ideal as a synthetic fuel because it is lightweight, highly abundant and its oxidation product (water) is environmentally benign, but storage remains a problem. Here we present recent developments in the search for innovative materials with high hydrogen-storage capacity.
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TL;DR: In this paper, the 2D counterpart of layered black phosphorus, which is called phosphorene, is introduced as an unexplored p-type semiconducting material and the authors find that the band gap is direct, depends on the number of layers and the in-layer strain, and significantly larger than the bulk value of 0.31-0.36 eV.
Abstract: We introduce the 2D counterpart of layered black phosphorus, which we call phosphorene, as an unexplored p-type semiconducting material. Same as graphene and MoS2, single-layer phosphorene is flexible and can be mechanically exfoliated. We find phosphorene to be stable and, unlike graphene, to have an inherent, direct, and appreciable band gap. Our ab initio calculations indicate that the band gap is direct, depends on the number of layers and the in-layer strain, and is significantly larger than the bulk value of 0.31–0.36 eV. The observed photoluminescence peak of single-layer phosphorene in the visible optical range confirms that the band gap is larger than that of the bulk system. Our transport studies indicate a hole mobility that reflects the structural anisotropy of phosphorene and complements n-type MoS2. At room temperature, our few-layer phosphorene field-effect transistors with 1.0 μm channel length display a high on-current of 194 mA/mm, a high hole field-effect mobility of 286 cm2/V·s, and an...
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TL;DR: A brief review of changes of sensitivity of conductometric semiconducting metal oxide gas sensors due to the five factors: chemical components, surface-modification and microstructures of sensing layers, temperature and humidity.
Abstract: Conductometric semiconducting metal oxide gas sensors have been widely used and investigated in the detection of gases. Investigations have indicated that the gas sensing process is strongly related to surface reactions, so one of the important parameters of gas sensors, the sensitivity of the metal oxide based materials, will change with the factors influencing the surface reactions, such as chemical components, surface-modification and microstructures of sensing layers, temperature and humidity. In this brief review, attention will be focused on changes of sensitivity of conductometric semiconducting metal oxide gas sensors due to the five factors mentioned above.
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TL;DR: In this paper, the authors present a review of hydrogen storage on materials with high specific surface area, hydrogen intercalation in metals and complex hydrides, and storage of hydrogen based on metals and water.
Abstract: Hydrogen storage is a materials science challenge because, for all six storage methods currently being investigated, materials with either a strong interaction with hydrogen or without any reaction are needed. Besides conventional storage methods, i.e. high pressure gas cylinders and liquid hydrogen, the physisorption of hydrogen on materials with a high specific surface area, hydrogen intercalation in metals and complex hydrides, and storage of hydrogen based on metals and water are reviewed. The goal is to pack hydrogen as close as possible, i.e. to reach the highest volumetric density by using as little additional material as possible. Hydrogen storage implies the reduction of an enormous volume of hydrogen gas. At ambient temperature and atmospheric pressure, 1 kg of the gas has a volume of 11 m3. To increase hydrogen density, work must either be applied to compress the gas, the temperature decreased below the critical temperature, or the repulsion reduced by the interaction of hydrogen with another material.
1,486 citations