Formation of additional amount of water due to functional oxygen group reduction leads to layer delamination. Reduction increases the C/O ratio to 2.8–10.3, decreases C sp3 content to 11.4–20.3 at% and also the content of C O C and C O groups, accompanied by increasing content of C OH and C OOH groups. All graphene oxide samples show the C/O ratio of 2.1–2.3, 26.5–32.1 at% of C sp3 bonds and high content of functional oxygen groups (hydroxyl-C OH, epoxy-C O C, carbonyl-C O, carboxyl-C OOH, water) (XPS). In graphene oxide and reduced graphene oxide prepared from the graphite the REELS indicates 8–11 and 7–10 layers. The REELS results are consistent with those by the XRD indicating 8 (FL-GOc) and 4 layers (FL-RGOc). The commercial graphene oxide (FL-GOc) shows a stacking nanostructure of about 22 × 6 nm average diameter by height with the distance of 0.9 nm between 6-7 graphene layers, whereas the respective reduced graphene oxide (FL-RGOc)-about 8 × 1 nm average diameter by height stacking nanostructure with the distance of 0.4 nm between 2-3 graphene layers (XRD). X-ray photoelectron spectroscopy (XPS) and reflection electron energy loss spectroscopy (REELS). Atomic layer deposited AlOx overlayers effectively suppress ambient degradation, allowing encapsulated BP FETs to ma.read more read lessĪbstract: The commercial and synthesised few-layer graphene oxide, prepared using oxidation reactions, and few-layer reduced graphene oxide samples were structurally and chemically investigated by the X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron spectroscopy methods, i.e. ![]() For unencapsulated BP field-effect transistors, the ambient degradation causes large increases in threshold voltage after 6 h in ambient, followed by a ∼103 decrease in FET current on/off ratio and mobility after 48 h. This interpretation is further supported by the observation that BP degradation occurs more rapidly on hydrophobic octadecyltrichlorosilane self-assembled monolayers and on H-Si(111) versus hydrophilic SiO2. Atomic force microscopy, electrostatic force microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy are employed to characterize the structure and chemistry of the degradation process, suggesting that O2 saturated H2O irreversibly reacts with BP to form oxidized phosphorus species. Draw a line through that point from one side of the circle to the other, and measure the length of that line to get the diameter.Abstract: Unencapsulated, exfoliated black phosphorus (BP) flakes are found to chemically degrade upon exposure to ambient conditions. ![]() The point where the two lines intersect will be the exact center of the circle. Draw a second line crossing the first one, connecting the other two points of the chords. Once you’ve drawn your chords, draw a diagonal line starting at the point where one chord intersects the edge of the circle, then connect it to the opposite point on the chord below. A chord is a straight line that connects any two points on the outer edge of the circle. The easiest way to do this is to draw two parallel chords across the circle. You can also measure the diameter of a drawing of a circle, but you’ll need to find the exact center of the circle to make an accurate measurement. So, if the area of the circle is 25 square centimeters, the diameter would be 2 x √(25/π), or approximately 5.64 centimeters. If you only know the area of the circle, use the formula diameter = 2 x √(area/π). For example, if your circle has a circumference of 23 inches, the diameter would be 23/π, or approximately 7.32 inches. Just divide the circumference by π to find the diameter. You can also find the diameter of a circle if you know its circumference, or the distance all the way around the outside of the circle. For instance, a circle with a radius of 2 cm would have a diameter of 4 cm. If you know the radius of the circle, all you have to do is multiply it by 2 to get the diameter. Depending on what other information you have about the circle, there are a few different ways to calculate the diameter. ![]() The diameter of a circle is the distance straight across the circle from one side to the other at its center.
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