We have measured the in-plane optical anisotropy （IPOA） of （1120） ZnO （a-plane） on （10]-2） sapphire （r-plane） by reflectance difference spectroscopy （RDS） at room temperature. Giant IPOA has been observed ...We have measured the in-plane optical anisotropy （IPOA） of （1120） ZnO （a-plane） on （10]-2） sapphire （r-plane） by reflectance difference spectroscopy （RDS） at room temperature. Giant IPOA has been observed be- tween the light polarized direction parallel and perpendicular to the c axis of ZnO, since the symmetry of a-plane is C2v. A sharp resonance has been observed near the fundamental band gap, which is induced by the polarization- depend band gap shift. The sharp line shape is attributed to the exciton transition. The spectra fitting and differential spectra indicate the polarization-depend band energies. The giant IPOA is possible enhanced by anisotropy strain along and perpendicular to the c axis in the a-plane.展开更多
The amorphous silicon nanoparticles （Si NPs） embedded in silicon nitride （SiNx） films prepared by helicon wave plasma-enhanced chemical vapor deposition （HWP-CVD） technique are studied. From Raman scattering inv...The amorphous silicon nanoparticles （Si NPs） embedded in silicon nitride （SiNx） films prepared by helicon wave plasma-enhanced chemical vapor deposition （HWP-CVD） technique are studied. From Raman scattering investigation, we determine that the deposited film has the structure of silicon nanocrystals embedded in silicon nitride （nc-Si/SiNx） thin film at a certain hydrogen dilution amount. The analysis of optical absorption spectra implies that the Si NPs is affected by quantum size effects and has the nature of an indirect-band-gap semiconductor. Further, considering the effects of the mean Si NP size and their dispersion on oscillator strength, and quantum-confinement, we obtain an analytical expression for the spectral absorbance of ensemble samples. Gaussian as well as lognormal size-distributions of the Si NPs are considered for optical absorption coefficient calculations. The influence of the particle size-distribution on the optical absorption spectra was systematically studied. We present the fitting of the optical absorption experimental data with our model and discuss the results.展开更多
电子信息技术是20世纪末兴起的技术,是21世纪技术的制高点,其中以HEMT(High Electron Mobility Transistor:高电子迁移率晶体管)为代表发展最为显著[1],本文分析其在全球和国内的专利申请情况,研究了全球和国内专利申请量随时间的变化,...电子信息技术是20世纪末兴起的技术,是21世纪技术的制高点,其中以HEMT(High Electron Mobility Transistor:高电子迁移率晶体管)为代表发展最为显著[1],本文分析其在全球和国内的专利申请情况,研究了全球和国内专利申请量随时间的变化,全球的申请的国家分布,主要的申请人,国内申请国家的分布,国内申请人的分布。展开更多
基金Project supported by the State Key Development Program for Basic Research of China(Nos.2013CB619306,2012CB921304)the National Natural Science Foundation of China(No.60990313)the National High Technology Research and Development Program of China(No.2011AA03A101)
文摘We have measured the in-plane optical anisotropy （IPOA） of （1120） ZnO （a-plane） on （10]-2） sapphire （r-plane） by reflectance difference spectroscopy （RDS） at room temperature. Giant IPOA has been observed be- tween the light polarized direction parallel and perpendicular to the c axis of ZnO, since the symmetry of a-plane is C2v. A sharp resonance has been observed near the fundamental band gap, which is induced by the polarization- depend band gap shift. The sharp line shape is attributed to the exciton transition. The spectra fitting and differential spectra indicate the polarization-depend band energies. The giant IPOA is possible enhanced by anisotropy strain along and perpendicular to the c axis in the a-plane.
基金Supported by the National Natural Science Foundation of China under Grant No.60940020the Natural Foundation of Hebei Province under Grant No.E2008000619
文摘The amorphous silicon nanoparticles （Si NPs） embedded in silicon nitride （SiNx） films prepared by helicon wave plasma-enhanced chemical vapor deposition （HWP-CVD） technique are studied. From Raman scattering investigation, we determine that the deposited film has the structure of silicon nanocrystals embedded in silicon nitride （nc-Si/SiNx） thin film at a certain hydrogen dilution amount. The analysis of optical absorption spectra implies that the Si NPs is affected by quantum size effects and has the nature of an indirect-band-gap semiconductor. Further, considering the effects of the mean Si NP size and their dispersion on oscillator strength, and quantum-confinement, we obtain an analytical expression for the spectral absorbance of ensemble samples. Gaussian as well as lognormal size-distributions of the Si NPs are considered for optical absorption coefficient calculations. The influence of the particle size-distribution on the optical absorption spectra was systematically studied. We present the fitting of the optical absorption experimental data with our model and discuss the results.
文摘电子信息技术是20世纪末兴起的技术,是21世纪技术的制高点,其中以HEMT(High Electron Mobility Transistor:高电子迁移率晶体管)为代表发展最为显著[1],本文分析其在全球和国内的专利申请情况,研究了全球和国内专利申请量随时间的变化,全球的申请的国家分布,主要的申请人,国内申请国家的分布,国内申请人的分布。
