目前,随着光电子芯片技术的高速发展,高频毫米波通信已成为目前宽带接入网络中的重要发展技术;因为采用外调制倍频方案的光生毫米波系统兼具收发毫米波信号的高效性和稳定性,且能充分利用现有电信网络中的光纤资源,因此,在实际中具备潜...目前,随着光电子芯片技术的高速发展,高频毫米波通信已成为目前宽带接入网络中的重要发展技术;因为采用外调制倍频方案的光生毫米波系统兼具收发毫米波信号的高效性和稳定性,且能充分利用现有电信网络中的光纤资源,因此,在实际中具备潜在应用价值。综述了光生毫米波倍频基本原理、典型倍频仿真或实验方案及其相关测试结果的研究进展;考虑到马赫-曾德尔调制器(Mach-Zehnder Modulator,MZM)作为倍频光生毫米波的关键电光器件,因此,分析了其中的关键工作参数;最后,对光载无线通信(Radio over Fiber,RoF)系统中光生毫米波技术的应用前景进行了展望。展开更多
The TiO 2 nanoparticle thin films have been sensitized in situ with CdS nanoparticles. The SPS measurement showed that large surface state density was present on the TiO 2 nanoparticles and the surface state can be ef...The TiO 2 nanoparticle thin films have been sensitized in situ with CdS nanoparticles. The SPS measurement showed that large surface state density was present on the TiO 2 nanoparticles and the surface state can be efficiently decreased by sensitization as well as selecting suitable heat treatment. Both the photocurrent response and the charge recombination kinetics in TiO 2 thin films were strongly influenced by trapping/detrapping of surface states. The slow photocurrent response of TiO 2 nanoparticulate thin films upon the illumination was attributed to the trap saturation effects. The semiconductor sensitization made the slow photoresponse disappeared and the steadystate photocurrent value increased drastically, which suggested that the sensitization of TiO 2 thin films with CdS could get a better charge separation and provide a simple alternative to minimize the effect of surface state on the photocurrent response.展开更多
文摘目前,随着光电子芯片技术的高速发展,高频毫米波通信已成为目前宽带接入网络中的重要发展技术;因为采用外调制倍频方案的光生毫米波系统兼具收发毫米波信号的高效性和稳定性,且能充分利用现有电信网络中的光纤资源,因此,在实际中具备潜在应用价值。综述了光生毫米波倍频基本原理、典型倍频仿真或实验方案及其相关测试结果的研究进展;考虑到马赫-曾德尔调制器(Mach-Zehnder Modulator,MZM)作为倍频光生毫米波的关键电光器件,因此,分析了其中的关键工作参数;最后,对光载无线通信(Radio over Fiber,RoF)系统中光生毫米波技术的应用前景进行了展望。
文摘The TiO 2 nanoparticle thin films have been sensitized in situ with CdS nanoparticles. The SPS measurement showed that large surface state density was present on the TiO 2 nanoparticles and the surface state can be efficiently decreased by sensitization as well as selecting suitable heat treatment. Both the photocurrent response and the charge recombination kinetics in TiO 2 thin films were strongly influenced by trapping/detrapping of surface states. The slow photocurrent response of TiO 2 nanoparticulate thin films upon the illumination was attributed to the trap saturation effects. The semiconductor sensitization made the slow photoresponse disappeared and the steadystate photocurrent value increased drastically, which suggested that the sensitization of TiO 2 thin films with CdS could get a better charge separation and provide a simple alternative to minimize the effect of surface state on the photocurrent response.
