Here,we propose a method to determine the thickness of the most common transition metal dichalcogenides (TMDCs) placed on the surface of transparent stamps,used for the deterministic placement of two-dimensional mater...Here,we propose a method to determine the thickness of the most common transition metal dichalcogenides (TMDCs) placed on the surface of transparent stamps,used for the deterministic placement of two-dimensional materials,by analyzing the red,green and blue channels of transmission-mode optical microscopy images of the samples.In particular,the blue channel transmittance shows a large and monotonic thickness dependence,making it a very convenient probe of the flake thickness.The method proves to be robust given the small flake-to-flake variation and the insensitivity to doping changes of MoS2.We also tested the method for MoSe2,WS2 and WSe2.These results provide a reference guide to identify the number of layers of this family of materials on transparent substrates only using optical microscopy.展开更多
Transparent conducting ZnO: Al thin films with good adhesion and low resistivity have been prepared on organic substrates and Corning 7059 glass substrates by r.f. magnetron-sputtering technique at low substrate tempe...Transparent conducting ZnO: Al thin films with good adhesion and low resistivity have been prepared on organic substrates and Corning 7059 glass substrates by r.f. magnetron-sputtering technique at low substrate temperature (25-210℃). Structural and photoelectric properties of the deposited films are investigated. The deposited films are polycrystalline with hexagonal structure and a preferred orientation with the c-axis perpendicular to the substrate. Only the (002) peak is observed. High quality films with resistivity as low as 1.0 × 10-3Ω·cm and 8.4 × 10-4Ω·cm, the average transmit-tance over 74% and 85% in the wavelength range of the visible spectrum have been obtained on different substrates.展开更多
Transparent conducting Co doped ZnO thin films have been fabricated by Ultrasonic spray. The thin films were deposited at three different substrate temperatures of 300, 350 and 400 ℃. The obtained films had a hexagon...Transparent conducting Co doped ZnO thin films have been fabricated by Ultrasonic spray. The thin films were deposited at three different substrate temperatures of 300, 350 and 400 ℃. The obtained films had a hexagonal wurtzite structure with a strong （002） preferred orientation. The maximum crystallite size value of the film deposited at 350 ℃ is 55.46 nm. Spectrophotometer （UV-vis） of a Co doped ZnO film deposited at 350 ℃ shows an average transmittance of about 90%. The band gap energy increased from 3.351 to 3.362 eV when the substrate temperature increased from 300 to 350 ℃. The electrical conductivity of the films deposited at 300, 350 and 400 ℃ were 7.424, 7.547 and 6.743 （Ω·cm）^-1 respectively. The maximum activation energy value of the films at 350 ℃ was 1.28 eV, indicating that the films exhibit a n-type semiconducting nature.展开更多
文摘Here,we propose a method to determine the thickness of the most common transition metal dichalcogenides (TMDCs) placed on the surface of transparent stamps,used for the deterministic placement of two-dimensional materials,by analyzing the red,green and blue channels of transmission-mode optical microscopy images of the samples.In particular,the blue channel transmittance shows a large and monotonic thickness dependence,making it a very convenient probe of the flake thickness.The method proves to be robust given the small flake-to-flake variation and the insensitivity to doping changes of MoS2.We also tested the method for MoSe2,WS2 and WSe2.These results provide a reference guide to identify the number of layers of this family of materials on transparent substrates only using optical microscopy.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 69876025) .
文摘Transparent conducting ZnO: Al thin films with good adhesion and low resistivity have been prepared on organic substrates and Corning 7059 glass substrates by r.f. magnetron-sputtering technique at low substrate temperature (25-210℃). Structural and photoelectric properties of the deposited films are investigated. The deposited films are polycrystalline with hexagonal structure and a preferred orientation with the c-axis perpendicular to the substrate. Only the (002) peak is observed. High quality films with resistivity as low as 1.0 × 10-3Ω·cm and 8.4 × 10-4Ω·cm, the average transmit-tance over 74% and 85% in the wavelength range of the visible spectrum have been obtained on different substrates.
文摘Transparent conducting Co doped ZnO thin films have been fabricated by Ultrasonic spray. The thin films were deposited at three different substrate temperatures of 300, 350 and 400 ℃. The obtained films had a hexagonal wurtzite structure with a strong （002） preferred orientation. The maximum crystallite size value of the film deposited at 350 ℃ is 55.46 nm. Spectrophotometer （UV-vis） of a Co doped ZnO film deposited at 350 ℃ shows an average transmittance of about 90%. The band gap energy increased from 3.351 to 3.362 eV when the substrate temperature increased from 300 to 350 ℃. The electrical conductivity of the films deposited at 300, 350 and 400 ℃ were 7.424, 7.547 and 6.743 （Ω·cm）^-1 respectively. The maximum activation energy value of the films at 350 ℃ was 1.28 eV, indicating that the films exhibit a n-type semiconducting nature.
