[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

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.

Metal oxide gas sensors: Sensitivity and influencing factors

Transparent conductors as solar energy materials: A panoramic review

Metal oxide gas sensors are predominant solid-state gas detecting devices for domestic, commercial and industrial applications, which have many advantages such as low cost, easy production, and compact size However, the performance of such sensors is significantly influenced by the morphology and structure of sensing materials, resulting in a great obstacle for gas sensors based on bulk materials or dense films to achieve highly-sensitive properties Lots of metal oxide nanostructures have been developed to improve the gas sensing properties such as sensitivity, selectivity, response speed, and so on Here, we provide a brief overview of metal oxide nanostructures and their gas sensing properties from the aspects of particle size, morphology and doping When the particle size of metal oxide is close to or less than double thickness of the space-charge layer, the sensitivity of the sensor will increase remarkably, which would be called "small size effect", yet small size of metal oxide nanoparticles will be compactly sintered together during the film coating process which is disadvantage for gas diffusion in them In view of those reasons, nanostructures with many kinds of shapes such as porous nanotubes, porous nanospheres and so on have been investigated, that not only possessed large surface area and relatively mass reactive sites, but also formed relatively loose film structures which is an advantage for gas diffusion Besides, doping is also an effective method to decrease particle size and improve gas sensing properties Therefore, the gas sensing properties of metal oxide nanostructures assembled by nanoparticles are reviewed in this article The effect of doping is also summarized and finally the perspectives of metal oxide gas sensor are given

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Metal Oxide Nanostructures and Their Gas Sensing Properties: A Review

Aligned Single‐Crystalline Si Nanowire Arrays for Photovoltaic Applications

Passivated emitter and rear contact (PERC) approach for small-scale laboratory industrial applications

Improvement of Electrical Characteristics of a-InSnZnO TFT Using Hydrogenated Gate Dielectric

The effect of low-temperature annealing treatment for various durations on the stability of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors was investigated. By this treatment, IGZO TFTs showed enhanced electrical characteristics and better stability under positive gate bias stress with increasing annealing time up to 18,000 s. For all VG stresses at different annealing times, the experimentally measured threshold voltage shift (ΔVth) as a function of stress time was precisely modeled with a stretched-exponential function. ΔVth was generated by carrier trapping, not by defect creation. It was verified that the decrease of interface trap state density (Nit) and free carriers resulted in the decrease of ΔVth with increasing annealing time. However, the characteristic trapping time of the carriers increased up to 5.3 × 103 s with increasing annealing time to 7,200 s and then decreased, implying that the interface quality between active layer/insulator was deteriorated with further annealing. In this study, successful fabrication of IGZO TFTs by post treatment with optimized duration is demonstrated for flexible display applications.

https://www.tpbin.com/Uploads/Subjects/9c2e918a-f785-43d6-be4d-f6e4e71b10fd.pdf

Trapping Time Characteristics of Carriers in a-InGaZnO Thin-Film Transistors Fabricated at Low Temperatures for Next-Generation Displays

In this study, we fabricated and characterized an organic photovoltaic (OPV) device with a pyromellitic dianhydride (PMDA)/lithium fluoride (LiF) cathode interfacial layer between poly(3-hexylthiophene?2,5-diyl)(P3HT)+[6,6]-phenyl C61?butyric acid methyl ester (PCBM) and Al. Compared to the OPV device with a LiF-only cathode interfacial layer having a power conversion efficiency (PCE) of 2.7%, the OPV device with the bilayer cathode interfacial structure [PMDA (0.3?nm)/LiF (0.7?nm)] exhibited a reduced resistance and a PCE value enhanced to 3.9% under an illumination condition of 100 mW cm?2?(AM1.5). The observed improvement of the OPV characteristics was attributed to the reduced leakage current of the device by the bilayer cathode interfacial layer.

Organic photovoltaic devices with the bilayer cathode interfacial structure of pyromellitic dianhydride and lithium fluoride

Thin films LiNbO₃ MFS (metal-ferroelectric-semiconductor) capacitor showed improved characteristics such as low interface trap density, low interaction with Si substrate, and large remanent polaization. This paper reports ferroelectric LiNbO₃ thin films grown directly on p-type Si (100) substrates by 13.56 ㎒ RF magnetron sputtering system for FRAM (ferroelectric random access memory) applications. RTA (rapid thermal anneal) treatment was performed for as-deposited films in an oxygen atmosphere at 600℃ for 60 sec. We learned from X-ray diffraction that the RTA treated films were changed from amorphous to poly-crystalline LiNbO₃ which exhibited (012), (015), (022), and (023) plane. Low temperature film growth and post RTA treatments improved the leakage current of LiNbO₃ films while keeping other properties almost as same as high substrate temperature grown samples. The leakage current density of LiNbO₃ films decreased from 10 -5 to 10 -7 A/㎠ after RTA treatment. Breakdown electric field of the films exhibited higher than 500 ㎸/㎝. C-V curves showed the clockwise hysteresis which represents ferroelectric switching characteristics. Calculated dielectric constant of thin film LiNbO₃ illustrated as high as 27.9. From ferroelectric measurement, the remanent polarization and coercive field were achieved as 1.37 μC/㎠ and 170 ㎸/㎝, respectively.

Junsin Yi

Papers

Passivated emitter and rear contact (PERC) approach for small-scale laboratory industrial applications

Improvement of Electrical Characteristics of a-InSnZnO TFT Using Hydrogenated Gate Dielectric

Trapping Time Characteristics of Carriers in a-InGaZnO Thin-Film Transistors Fabricated at Low Temperatures for Next-Generation Displays

Organic photovoltaic devices with the bilayer cathode interfacial structure of pyromellitic dianhydride and lithium fluoride

Effect of RTA Treatment on LiNbO₃ MFS Memory Capacitors