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We report on the photoluminescence enhancement of 1.3 μm InAs quantum dots (QDs) epitaxially grown on an ultrathin 250 nm GaAs buffer on a Si substrate. Decreasing the GaAs buffer thickness from 1000 to 250 nm was found to not only increase the coalesced QD density from 6.5 × 10

Current infrared thermal image sensors are mainly based on planar firm substrates, but the rigid form factor appears to restrain the versatility of their applications. For wearable health monitorin...

Significance Metformin is the most commonly prescribed drug for the treatment of type 2 diabetes mellitus, yet the mechanism by which it lowers plasma glucose concentrations has remained elusive. Most studies to date have attributed metformin’s glucose-lowering effects to inhibition of complex I activity. Contrary to this hypothesis, we show that inhibition of complex I activity in vitro and in vivo does not reduce plasma glucose concentrations or inhibit hepatic gluconeogenesis. We go on to show that metformin, and the related guanides/biguanides, phenformin and galegine, inhibit complex IV activity at clinically relevant concentrations, which, in turn, results in inhibition of glycerol-3-phosphate dehydrogenase activity, increased cytosolic redox, and selective inhibition of glycerol-derived hepatic gluconeogenesis both in vitro and in vivo.

Current infrared thermal image sensors are mainly based on planar firm substrates, but the rigid form factor appears to restrain the versatility of their applications. For wearable health monitoring and implanted biomedical sensing, transfer of active device layers onto a flexible substrate is required while controlling the high-quality crystalline interface. Here, we demonstrate high-detectivity flexible InAs thin-film mid-infrared photodetector arrays through high-yield wafer bonding and a heteroepitaxial lift-off process. An abruptly graded In

Flexible mid-infrared photodetectors are essential to realize advanced imaging applications, including wearable healthcare monitoring, security, and biomedical applications. Here, we demonstrate high-performance flexible p-i-n InAs thin-film photodetectors with an optimal In0.8Al0.2As barrier layer. This In0.8Al0.2As barrier inserted between p-InAs and UID-InAs layer reduced leakage currents by a factor of 283 by blocking the flow of electrons. The fabricated flexible device exhibited relatively low dark current densities of 1.03×10−5 at 0 V and 0.85 A/cm2 at −0.5 V, comparable to both commercially available and reported homoepitaxially-grown InAs detectors. Also, the high mechanical robustness and excellent reliability of our flexible InAs photodetector were confirmed by bending tests under various curvatures and bending cycles.

We demonstrate a low threading dislocation density (TDD) and smooth surface InAs layer epitaxially grown on Si by suppressing phase separation of InxAl1−xAs (x = 0 to 1) graded buffer and by inserting a tensile-strained In0.95Al0.05As dislocation filter layer. While keeping the total III–V layer below 2.7 μm to avoid thermal cracks, we have achieved a sixfold reduction of TDD in InAs on Si compared to the unoptimized structure. We found a strong correlation between the metamorphic InAs surface roughness and TDD as a function of InxAl1−xAs buffer thickness. An optimal thickness of 175 nm was obtained where both phase separation and 3D islanding growth were suppressed. Moreover, a tensile-strained In0.95Al0.05As dislocation filter layer and high growth temperature of the InAs cap layer further assisted the dislocation reduction process, which led to a TDD to 1.37 × 108 cm−2. Finally, an InAs p-i-n photodetector grown on the optimized InAs/Si template confirmed its high quality by showing an improved responsivity from 0.16 to 0.32 A/W at a 2 μm wavelength.