An exponential-doping structure is successfully applied to the preparation of AlGaAs/GaAs photocathodes through the metalorganic chemical vapor deposition(MOCVD)technique.The experimental results show that the quantum...An exponential-doping structure is successfully applied to the preparation of AlGaAs/GaAs photocathodes through the metalorganic chemical vapor deposition(MOCVD)technique.The experimental results show that the quantum efficiency in the entire waveband region for the exponential-doping photocathodes grown by MOCVD is remarkably enhanced as compared to those grown by molecular beam epitaxy.As a result of the improved built-in electric fields and cathode performance parameters,the photoemission characteristics for the MOCVD-grown transmission-mode and reflection-mode AlGaAs/GaAs photocathodes are different over the wavelength region of interest.展开更多
For the frequency range of I kHz-lOMHz, the interface state density of Ni contacts on p-GaN is studied using capacitance-voltage （C-V） and conductance-frequency-voltage （G-f-V） measurements at room temperature. To...For the frequency range of I kHz-lOMHz, the interface state density of Ni contacts on p-GaN is studied using capacitance-voltage （C-V） and conductance-frequency-voltage （G-f-V） measurements at room temperature. To obtain the real capacitance and interface state density of the Ni/p-GaN structures, the effects of the series resistance （Rs） on high-frequency （SMHz） capacitance values measured at a reverse and a forward bias are investigated. The mean interface state densities obtained from the CHF-CLF capacitance and the conductance method are 2 ×1012 e V-1 cm-2 and 0.94 × 1012 eV-1 cm-2, respectively. Furthermore, the interface state density derived from the conductance method is higher than that reported from the Ni/n-GaN in the literature, which is ascribed to a poor crystal quality and to a large defect density of the Mg-doped p-GaN.展开更多
We investigate the structure of yrast bands in the transuranium nuclei ^(242)Pu and ^(244)Pu in the framework of the projected shell model,which is a fully quantum mechanical and microscopic approach.It is found that ...We investigate the structure of yrast bands in the transuranium nuclei ^(242)Pu and ^(244)Pu in the framework of the projected shell model,which is a fully quantum mechanical and microscopic approach.It is found that an appropriate modification of the standard Nilsson spin-orbital parameters in the N =6 proton shell is necessary to correctly describe the high-spin backbending phenomenon in nucleus ^(244)Pu.In order to test whether this modification is correct,the same modified parameters are used to calculate the yrast band of its neighboring isotope ^(242)Pu.It is found that without this modification,a backbending will occur at spin I =20,which is not supported by the experimental data.展开更多
基金the National Natural Science Foundation of China under Grant Nos 61067001,61240042 and 61261009the Key Science and Technology Project of Henan Province of China under Grant No 112102210202.
文摘An exponential-doping structure is successfully applied to the preparation of AlGaAs/GaAs photocathodes through the metalorganic chemical vapor deposition(MOCVD)technique.The experimental results show that the quantum efficiency in the entire waveband region for the exponential-doping photocathodes grown by MOCVD is remarkably enhanced as compared to those grown by molecular beam epitaxy.As a result of the improved built-in electric fields and cathode performance parameters,the photoemission characteristics for the MOCVD-grown transmission-mode and reflection-mode AlGaAs/GaAs photocathodes are different over the wavelength region of interest.
基金Supported by the Natural Science Foundation of Jiangxi Province under Grant No 20133ACB20005the Key Program of National Natural Science Foundation of China under Grant No 41330318+3 种基金the Key Program of Science and Technology Research of Ministry of Education under Grant No NRE1515the Foundation of Training Academic and Technical Leaders for Main Majors of Jiangxi Province under Grant No 20142BCB22006the Research Foundation of Education Bureau of Jiangxi Province under Grant No GJJ14501the Engineering Research Center of Nuclear Technology Application(East China Institute of Technology)Ministry of Education under Grant NoHJSJYB2016-1
文摘For the frequency range of I kHz-lOMHz, the interface state density of Ni contacts on p-GaN is studied using capacitance-voltage （C-V） and conductance-frequency-voltage （G-f-V） measurements at room temperature. To obtain the real capacitance and interface state density of the Ni/p-GaN structures, the effects of the series resistance （Rs） on high-frequency （SMHz） capacitance values measured at a reverse and a forward bias are investigated. The mean interface state densities obtained from the CHF-CLF capacitance and the conductance method are 2 ×1012 e V-1 cm-2 and 0.94 × 1012 eV-1 cm-2, respectively. Furthermore, the interface state density derived from the conductance method is higher than that reported from the Ni/n-GaN in the literature, which is ascribed to a poor crystal quality and to a large defect density of the Mg-doped p-GaN.
基金Supported by Suranaree University of Technology under Grant No 15/2553the National Basic Research Development Program of China under Grant No 2007CB815003the National Natural Science Foundation of China under Grant Nos 10975190,11065001,10975019,10675170 and 61067001.
文摘We investigate the structure of yrast bands in the transuranium nuclei ^(242)Pu and ^(244)Pu in the framework of the projected shell model,which is a fully quantum mechanical and microscopic approach.It is found that an appropriate modification of the standard Nilsson spin-orbital parameters in the N =6 proton shell is necessary to correctly describe the high-spin backbending phenomenon in nucleus ^(244)Pu.In order to test whether this modification is correct,the same modified parameters are used to calculate the yrast band of its neighboring isotope ^(242)Pu.It is found that without this modification,a backbending will occur at spin I =20,which is not supported by the experimental data.
