Physical properties of transparent perovskite oxides (Ba,La)SnO3 with high electrical mobility at room temperature

Transparent electronic materials are increasingly in demand for a variety of optoelectronic applications. BaSnO3 is a semiconducting oxide with a large band gap of more than 3.1 eV. Recently, we discovered that La doped BaSnO3 exhibits unusually high electrical mobility of 320 cm^2(Vs)^-1 at room temperature and superior thermal stability at high temperatures [H. J. Kim et al. Appl. Phys. Express. 5, 061102 (2012)]. Following that work, we report various physical properties of (Ba,La)SnO3 single crystals and films including temperature-dependent transport and phonon properties, optical properties and first-principles calculations. We find that almost doping-independent mobility of 200-300 cm^2(Vs)^-1 is realized in the single crystals in a broad doping range from 1.0x10^19 to 4.0x10^20 cm^-3. Moreover, the conductivity of ~10^4 ohm^-1cm^-1 reached at the latter carrier density is comparable to the highest value. We attribute the high mobility to several physical properties of (Ba,La)SnO3: a small effective mass coming from the ideal Sn-O-Sn bonding, small disorder effects due to the doping away from the SnO2 conduction channel, and reduced carrier scattering due to the high dielectric constant. The observation of a reduced mobility of ~70 cm^2(Vs)^-1 in the film is mainly attributed to additional carrier-scatterings which are presumably created by the lattice mismatch between the substrate SrTiO3 and (Ba,La)SnO3. The main optical gap of (Ba,La)SnO3 single crystals remained at about 3.33 eV and the in-gap states only slightly increased, thus maintaining optical transparency in the visible region. Based on these, we suggest that the doped BaSnO3 system holds great potential for realizing all perovskite-based, transparent high-frequency high-power functional devices as well as highly mobile two-dimensional electron gas via interface control of heterostructured films.Comment: 31 pages, 7 figure

High Mobility in a Stable Transparent Perovskite Oxide

We discovered that La-doped BaSnO3 with the perovskite structure has an unprecedentedly high mobility at room temperature while retaining its optical transparency. In single crystals, the mobility reached 320 cm^2(Vs)^-1 at a doping level of 8x10^19 cm^-3, constituting the highest value among wide-band-gap semiconductors. In epitaxial films, the maximum mobility was 70 cm^2(Vs)^-1 at a doping level of 4.4x10^20 cm^-3. We also show that resistance of (Ba,La)SnO3 changes little even after a thermal cycle to 530 Deg. C in air, pointing to an unusual stability of oxygen atoms and great potential for realizing transparent high-frequency, high-power functional devices.Comment: 15 pages, 3 figure

Effects of Biochar on Methane Emissions and Crop Yields in East Asian Paddy Fields: A Regional Scale Meta-Analysis

Biochar emerged as a potential solution to mitigating greenhouse gas emissions, though previous studies obtained variable results regarding its effects on methane (CH4) emissions and crop yields. Global meta-analyses were conducted regarding the effectiveness of biochar, though regional meta-analyses are still needed. We performed a meta-analysis of 43 published papers to obtain the central tendency of the response to biochar application in East Asian rice paddies. Biochar application significantly reduced methane emissions while increasing the soil organic carbon (SOC) content and crop yield. We identified the most significant influencing factors on the CH4 emissions, SOC content, and crop yield. Our findings provide a scientific basis for the application of biochar to East Asian rice paddies, as well as to study the effects of biochar application in East Asian rice paddies. The numbers in parentheses represent the sample sizes

Ab417 binds to L1CAM-expressing ICC cells and reduces L1CAM levels at the membrane.

<p>(A) Confocal microscopic analysis of Ab417 internalization. SCK-L1 cells were preincubated with Ab417 (10 μg/mL) for the indicated times. Membrane L1CAM-bound Ab417 was detected using anti-Human IgG(H+L) Cross Adsorbed DyLight 594 (red), and internalized Ab417 was detected using anti-human IgG (Fc-specific)-FITC (green). (B) Choi-CK cells were incubated with Ab417 (10 μg/mL) for the indicated times, and the membrane L1CAM was detected by western blot analysis using A10-A3 and pan-cadherin as a loading control. Control (c) indicates the cells that were incubated for 6 h without Ab417. (C) Confocal microscopic images of L1CAM staining of PBS (up)- or Ab417 (down)-treated Choi-CK tumors. The images were taken at x400 magnification. L1CAM index (D) are represented as a percentage of positively-stained area comparing to total area.</p

Anti-tumor efficacy of gemcitabine or cisplatin in a Choi-CK xenograft model.

<p>Drug at indicated dose was <i>i</i>.<i>p</i>. injected twice a week for 3 or 4 weeks, and tumor volume (A) and tumor weight (B) were determined. Each point indicates the mean ± s.d. <i>p</i> < 0.05 (*) and <i>p</i> < 0.01 (**), significant difference from the saline-treated group by Dunnett’s <i>t</i>-test. <i>p</i> < 0.05 (^#) and <i>p</i> < 0.01 (^##), significant difference from the saline group by Steel’s test.</p

Anti-tumor efficacy of combined treatment with Ab417 and gemcitabine or cisplatin in a Choi-CK model.

<p>Tumor volume (A and C) and tumor weight (B and D) are represented. Each point indicates the mean ± s.d (<i>n</i> = 8). <i>p</i> < 0.05 (*) and <i>p</i> < 0.01 (**), significant difference from the saline group by Dunnett’s <i>t</i>-test. <i>p</i> < 0.05 (^#) and <i>p</i> < 0.01 (^##), significant difference from the saline group by Steel’s test.</p