Thin films of tungsten （W）-doped thermochromic vanadium dioxide （VO2） were deposited onto soda-lime glass and fused silica by radio frequency magnetron sputtering. The doped VO2 films were characterized by X-ray d...Thin films of tungsten （W）-doped thermochromic vanadium dioxide （VO2） were deposited onto soda-lime glass and fused silica by radio frequency magnetron sputtering. The doped VO2 films were characterized by X-ray diffraction, optical transmittance measurement, and near field optical microscopy with Raman spectroscopy. X-ray diffraction patterns show that the （011） peak of W-doped thermochromic VO2 film shifts to a lower diffraction angle with the increase of W concentration. The optical measurements indicated that the transmittance change （AT） at wavelength of 2500 nm drops from 65% （AT at 35 ℃ and 80 ℃ for undoped VO2 film） to 38% （AT at 30 ℃ and 42 ℃ for the doped VO2 film）. At the same time, phase transition temperature drops from 65 ℃ to room temperature or lower with the increase of W concentration. Near field optical microscopy image shows that the surface of W-doped VO2 film is smooth. Raman results show that the main Raman modes of W-doped VO2 are centered at 614 cm 1, the same as that of undoped VO2, suggesting no Raman mode changes for lightly W-doped VO2 at room temperature, due to no phase transition appearing under this condition.展开更多
An original numerical model, based on the standard Berg model, is used to simulate the growth mechanism of Ndoped VOx deposited with changing oxygen flow in the reactive gas mixture. In order to compare with the numer...An original numerical model, based on the standard Berg model, is used to simulate the growth mechanism of Ndoped VOx deposited with changing oxygen flow in the reactive gas mixture. In order to compare with the numerical model, N-doped VOx films are prepared by reactive magnetron sputtering from a metallic vanadium target immersed in a reactive gas mixture of Ar＋O2＋N2. Both experimental and numerical results show that the addition of N2 to the process alleviates the hysteresis effect with respect to the oxygen supply. Film compositions obtained from the XPS analysis are compared to the numerical results and the agreement is satisfactory. The results also show that the compound of VN is only found at very low O concentration because of the replacement reaction of VN by O2 atoms with higher oxygen flow rate.展开更多
采用射频溅射磁控溅射技术在Ar+H2气氛下,以V2O5为溅射靶材在玻璃基片上制备了H掺杂VO2(HVO2)薄膜,研究了H2流量和退火处理对HVO2薄膜的结构、光电性能和热稳定性的影响。结果表明:H2流量可以控制薄膜中H的含量,微量H的掺杂使HVO2薄膜...采用射频溅射磁控溅射技术在Ar+H2气氛下,以V2O5为溅射靶材在玻璃基片上制备了H掺杂VO2(HVO2)薄膜,研究了H2流量和退火处理对HVO2薄膜的结构、光电性能和热稳定性的影响。结果表明:H2流量可以控制薄膜中H的含量,微量H的掺杂使HVO2薄膜相变温度降低到室温附近,过量的H掺杂会使薄膜处于金属态。当500℃下退火3 h后,薄膜物相、相变等特征明显变化,此时薄膜中的H不能稳定存在于VO2晶格而溢出薄膜。当退火温度≤450℃、退火时间≤6 h时,薄膜保持较高的稳定性,这为室温附近使用HVO2薄膜提供了基础。另外,随H2流量增加,薄膜的平均透射率小幅度增加,最终稳定在37%左右。随着退火温度的增加,未引入H2制备的VO2薄膜的平均透射率在400℃退火后为30.9%,在450和500℃退火后为35.8%左右。H2流量为0.1~0.5 m L/min时制备的样品在3种退火温度下的透射率均保持在38%左右。展开更多
基金supported by the Chinese Universities Scientific Fund (Grant No. 2013QJ007)the Science Fund of China Agricultural University (Grant No. 2007037)the Major Project Foundation of Science and Technology Innovation in Advanced Education (Grant No. 21010112)
文摘Thin films of tungsten （W）-doped thermochromic vanadium dioxide （VO2） were deposited onto soda-lime glass and fused silica by radio frequency magnetron sputtering. The doped VO2 films were characterized by X-ray diffraction, optical transmittance measurement, and near field optical microscopy with Raman spectroscopy. X-ray diffraction patterns show that the （011） peak of W-doped thermochromic VO2 film shifts to a lower diffraction angle with the increase of W concentration. The optical measurements indicated that the transmittance change （AT） at wavelength of 2500 nm drops from 65% （AT at 35 ℃ and 80 ℃ for undoped VO2 film） to 38% （AT at 30 ℃ and 42 ℃ for the doped VO2 film）. At the same time, phase transition temperature drops from 65 ℃ to room temperature or lower with the increase of W concentration. Near field optical microscopy image shows that the surface of W-doped VO2 film is smooth. Raman results show that the main Raman modes of W-doped VO2 are centered at 614 cm 1, the same as that of undoped VO2, suggesting no Raman mode changes for lightly W-doped VO2 at room temperature, due to no phase transition appearing under this condition.
文摘An original numerical model, based on the standard Berg model, is used to simulate the growth mechanism of Ndoped VOx deposited with changing oxygen flow in the reactive gas mixture. In order to compare with the numerical model, N-doped VOx films are prepared by reactive magnetron sputtering from a metallic vanadium target immersed in a reactive gas mixture of Ar＋O2＋N2. Both experimental and numerical results show that the addition of N2 to the process alleviates the hysteresis effect with respect to the oxygen supply. Film compositions obtained from the XPS analysis are compared to the numerical results and the agreement is satisfactory. The results also show that the compound of VN is only found at very low O concentration because of the replacement reaction of VN by O2 atoms with higher oxygen flow rate.
文摘采用射频溅射磁控溅射技术在Ar+H2气氛下,以V2O5为溅射靶材在玻璃基片上制备了H掺杂VO2(HVO2)薄膜,研究了H2流量和退火处理对HVO2薄膜的结构、光电性能和热稳定性的影响。结果表明:H2流量可以控制薄膜中H的含量,微量H的掺杂使HVO2薄膜相变温度降低到室温附近,过量的H掺杂会使薄膜处于金属态。当500℃下退火3 h后,薄膜物相、相变等特征明显变化,此时薄膜中的H不能稳定存在于VO2晶格而溢出薄膜。当退火温度≤450℃、退火时间≤6 h时,薄膜保持较高的稳定性,这为室温附近使用HVO2薄膜提供了基础。另外,随H2流量增加,薄膜的平均透射率小幅度增加,最终稳定在37%左右。随着退火温度的增加,未引入H2制备的VO2薄膜的平均透射率在400℃退火后为30.9%,在450和500℃退火后为35.8%左右。H2流量为0.1~0.5 m L/min时制备的样品在3种退火温度下的透射率均保持在38%左右。
