Aluminum-doped zinc oxide (AZO) thin films were deposited on sapphire (002) and glass substrates by two different sputtering techniques radio frequency magnetron cosputtering of AZO and ZnO targets and sputtering of a...Aluminum-doped zinc oxide (AZO) thin films were deposited on sapphire (002) and glass substrates by two different sputtering techniques radio frequency magnetron cosputtering of AZO and ZnO targets and sputtering of an AZO target. The dependence of the photoluminescence (PL) and transmittance properties of the AZO films deposited by cosputtering and sputtering on the AZO/ZnO target power ratio, R and the O2/Ar flow ratio, r were investigated, respectively. Only a deep level emission peak appears in the PL spectra of cosputtered AZO films whereas both UV emission and deep level emission peaks are observed in the PL spectra of sputtered AZO films. The absorption edges in the transmittance spectra of the AZO films shift to the lower wavelength region as R and r increase. Effects of crystallinity, surface roughness, PL on the transmittance of the AZO films were also explained using the X-ray diffraction (XRD), atomic force microscopy (AFM), and PL analysis results.展开更多
GaN nanorods have successfully been synthesized on Si(111) substrates via ammoniating ZnO/Ga2O3 films at 950 degrees C. Ga2O3 thin films and ZnO middle layers were deposited in turn on Si(111) substrates by r.f. magne...GaN nanorods have successfully been synthesized on Si(111) substrates via ammoniating ZnO/Ga2O3 films at 950 degrees C. Ga2O3 thin films and ZnO middle layers were deposited in turn on Si(111) substrates by r.f. magnetron sputtering system. ZnO volatilized at 950 degrees C in the ammonia ambience and Ga2O3 reacted to NH3 to fabricate GaN nanorods in the later ammoniating process. The volatilization of ZnO layers played an important role in the fabrication. The structure and composition of the GaN nanorods were studied by X-ray diffraction (XRD) and Fourier transform infrared spectrophotometer (FTIR). The morphology of GaN nanorods was investigated using scanning electron microscopy (SEM) and transmission electronic microscope (TEM). The analyses of measured results revealed that GaN nanorods with hexagonal wurtzite structure were prepared by this method.展开更多
运用回归技术并结合 SEM的测试结果，对影响 ZnO－ Al 2O 3系陶瓷电阻及电阻温度特性的线性化机制进行了探讨。研究表明， Al 2O 3、 MgO的掺杂及烧成工艺均对材料的电阻率和电阻温度系数有较为明显的影响，镁掺杂对材料的电子激活能有...运用回归技术并结合 SEM的测试结果，对影响 ZnO－ Al 2O 3系陶瓷电阻及电阻温度特性的线性化机制进行了探讨。研究表明， Al 2O 3、 MgO的掺杂及烧成工艺均对材料的电阻率和电阻温度系数有较为明显的影响，镁掺杂对材料的电子激活能有较大的影响。当材料的电子激活能值较低时，通过回归发现其阻温特性具有较好的线性，符合麦克劳林公式近似。展开更多
（1120）ZnO film/R-sapphire substrate structure is promising for high frequency acoustic wave devices. The propagation characteristics of SAWs, including the Rayleigh waves along [0001] direction and Love waves along ...（1120）ZnO film/R-sapphire substrate structure is promising for high frequency acoustic wave devices. The propagation characteristics of SAWs, including the Rayleigh waves along [0001] direction and Love waves along [1100] direction, are investigated by using 3 dimensional finite element method （3D-FEM）. The phase velocity （vp）, electromechanical coupling coefficient （k2）, temperature coefficient of frequency （TCF） and reflection coefficient （r） of Rayleigh wave and Love wave devices are theoretically analyzed. Furthermore, the influences of ZnO films with different crystal orientation on SAW properties are also investigated. The results show that the 1st Rayleigh wave has an exceedingly large/d of 4.95% in （90°, 90°, 0°） （1120）ZnO film/R-sapphire substrate associated with a phase velocity of 5300 m/s; and the 0th Love wave in （0°, 90°, 0°） （1120）ZnO film/R-sapphire substrate has a maximum k2 of 3.86% associated with a phase velocity of 3400 m/s. And （1120）ZnO film/R-sapphire substrate structures can be used to design temperature-compensated and wide-band SAW devices. All of the results indicate that the performances of SAW devices can be optimized by suitably selecting ZnO films with different thickness and crystal orientations deposited on R-sapphire substrates.展开更多
文摘Aluminum-doped zinc oxide (AZO) thin films were deposited on sapphire (002) and glass substrates by two different sputtering techniques radio frequency magnetron cosputtering of AZO and ZnO targets and sputtering of an AZO target. The dependence of the photoluminescence (PL) and transmittance properties of the AZO films deposited by cosputtering and sputtering on the AZO/ZnO target power ratio, R and the O2/Ar flow ratio, r were investigated, respectively. Only a deep level emission peak appears in the PL spectra of cosputtered AZO films whereas both UV emission and deep level emission peaks are observed in the PL spectra of sputtered AZO films. The absorption edges in the transmittance spectra of the AZO films shift to the lower wavelength region as R and r increase. Effects of crystallinity, surface roughness, PL on the transmittance of the AZO films were also explained using the X-ray diffraction (XRD), atomic force microscopy (AFM), and PL analysis results.
基金This work was financially supported by the Key Research Program of National Natural Science Foundation of China (No. 90301002 and No. 90201025).
文摘GaN nanorods have successfully been synthesized on Si(111) substrates via ammoniating ZnO/Ga2O3 films at 950 degrees C. Ga2O3 thin films and ZnO middle layers were deposited in turn on Si(111) substrates by r.f. magnetron sputtering system. ZnO volatilized at 950 degrees C in the ammonia ambience and Ga2O3 reacted to NH3 to fabricate GaN nanorods in the later ammoniating process. The volatilization of ZnO layers played an important role in the fabrication. The structure and composition of the GaN nanorods were studied by X-ray diffraction (XRD) and Fourier transform infrared spectrophotometer (FTIR). The morphology of GaN nanorods was investigated using scanning electron microscopy (SEM) and transmission electronic microscope (TEM). The analyses of measured results revealed that GaN nanorods with hexagonal wurtzite structure were prepared by this method.
文摘运用回归技术并结合 SEM的测试结果，对影响 ZnO－ Al 2O 3系陶瓷电阻及电阻温度特性的线性化机制进行了探讨。研究表明， Al 2O 3、 MgO的掺杂及烧成工艺均对材料的电阻率和电阻温度系数有较为明显的影响，镁掺杂对材料的电子激活能有较大的影响。当材料的电子激活能值较低时，通过回归发现其阻温特性具有较好的线性，符合麦克劳林公式近似。
基金supported by the National Natural Science Foundation of China(Grant No.11304160)the Natural Science Foundation of Jiangsu Higher Education Institutions of China(Grant No.13KJB140008)the Foundation of Nanjing University of Posts and Telecommunications(Grant No.NY213018)
文摘（1120）ZnO film/R-sapphire substrate structure is promising for high frequency acoustic wave devices. The propagation characteristics of SAWs, including the Rayleigh waves along [0001] direction and Love waves along [1100] direction, are investigated by using 3 dimensional finite element method （3D-FEM）. The phase velocity （vp）, electromechanical coupling coefficient （k2）, temperature coefficient of frequency （TCF） and reflection coefficient （r） of Rayleigh wave and Love wave devices are theoretically analyzed. Furthermore, the influences of ZnO films with different crystal orientation on SAW properties are also investigated. The results show that the 1st Rayleigh wave has an exceedingly large/d of 4.95% in （90°, 90°, 0°） （1120）ZnO film/R-sapphire substrate associated with a phase velocity of 5300 m/s; and the 0th Love wave in （0°, 90°, 0°） （1120）ZnO film/R-sapphire substrate has a maximum k2 of 3.86% associated with a phase velocity of 3400 m/s. And （1120）ZnO film/R-sapphire substrate structures can be used to design temperature-compensated and wide-band SAW devices. All of the results indicate that the performances of SAW devices can be optimized by suitably selecting ZnO films with different thickness and crystal orientations deposited on R-sapphire substrates.
