Chinese Physics Letters
Electron correlation in triple differential cross sections for ionization of atomic hydrogen by electron impact is analysed for the case of coplanar asymmetric geometry within the framework of the two-potential formulae. Based on the approximations of projectile and faster-electron plane wave, the transition matrix element is analytically expressed to be a product of two factors: the correlation factor of two electrons in the final channel and the structure-scattering factor. The contribution of both the factors to the angular distribution of the triple differential cross section is calculated. The present results are compared with the experimental data and the other theoretical calculations for the incident energy of 150eV.
关键词:
differential cross-sections;atomic-hydrogen;energy
卢赛
,
王茺
,
王文杰
,
杨宇
人工晶体学报
将剂量为2×1016 cm-2的C+以60 keV的能量注入到SiO2薄膜中并进行了退火处理.从样品的室温光致发光(PL)光谱中观察到六个PL峰,其峰位分别处于2.601 eV、2.857 eV、3.085 eV、3.249 eV、3.513 eV和3.751 eV.其中3.249 eV处的PL峰与4H-SiC有关.而对于尚未见报道的3.751 eV处PL峰,进行了红外吸收和荧光激发(PLE)测试:在PLE谱4.429 eV处显示出一个对应于3.751 eV处的激发峰.在红外吸收谱上证实0.205 eV(1650cm-1)处的吸收峰与3.751 eV处发光峰的起源相关,从而推断在3.751 eV处的PL峰应起源于氧空位缺陷.
关键词:
SiC纳米晶
,
SiO2薄膜
,
氧空位
范翊
,
金华
,
罗劲松
,
杨为有
,
张立功
,
谢志鹏
,
安立楠
稀有金属材料与工程
采用催化裂解有机前驱体方法制备出单晶a-Si3N4纳米带,研究了纳米带的吸收光谱、光致发光(PL)及激发(PLE)光谱.吸收光谱表明约5.0eV禁带宽度的纳米带是间接带半导体吸收.室温下纳米带的PL光谱在1.8eV, 2.3eV和3.0eV处有3个宽峰.PLE光谱显示在能隙中存在多个能级.
关键词:
a-Si3N4
,
单晶
,
吸收
,
光致发光
许岗
,
李高宏
,
介万奇
人工晶体学报
为研究HgI2晶体结构缺陷与光吸收的关系,测试了晶体的UV和中红外透过光谱.结果表明,波长约为580 nm时,存在着本征吸收限;波长大于580 nm时,随波长增加,晶体对光的吸收减小,透过率达到45%以上;在1000～2500 nm范围内,UV光谱存在四个明显的光吸收带,对应的入射光能量分别为0.79±0.01 eV,0.72 eV,0.57±0.01 eV 和0.53 eV.中红外透过曲线随波长增加而增大,透过率为39%～68%.通过M/HgI2的I～t曲线,采用简单能级模型进一步确认了生长的HgI2晶体存在0.79±0.01 eV和0.72 eV两个陷阱能级.分析认为,HgI2晶体层间的相对移动形成的结构缺陷造成1572.5 nm(0.79±0.01 eV)和1729.2 nm(0.72 eV)处的吸收,晶体缺碘造成2117.5 nm(0.57±0.01 eV)处的吸收和汞空位造成2305.8 nm(0.53 eV)的吸收.在中红外波段,晶体结构缺陷造成了显著的晶格吸收.严格控制原料的化学计量比有利于减少HgI2晶体的结构缺陷,提高晶体的光学性能.
关键词:
碘化汞
,
结构缺陷
,
自由载流子吸收
Chinese Physics Letters
Electroluminescence (EL) is observed from the Au/Si-rich SiO2 film/p-Si diodes, in which the Si-rich SiO2 films are scored deliberately by a diamond tip. The EL intensity of the scored diode annealed at 800 degreesC is about 6 times of that of the unscored counterpart. The EL spectrum of the unscored diode could be decomposed into two Gaussian luminescence bands with peaks at about 1.83 and 2.23eV, while for the EL spectrum of the scored diode, an additional Gaussian band at about 3.0eV appears, and the 1.83-eV peak increases significantly in intensity. The photoluminescence (PL) spectrum of an unscored Si-rich SiO2 film has only one band peaking at about 1.48eV, whereas the PL spectrum of the scored one has two bands at about 1.48 and 1.97eV. We consider that the high-density defect regions produced by the scoring provide new luminescence centres and become some types of nonradiative centres in the Si oxide layer, which thus result in changes of the EL and PL spectra.
关键词:
visible photoluminescence;amorphous sio2;porous silicon;luminescence;light
李成斌
,
徐至展
,
贾天卿
,
冯东海
,
孙海轶
,
李晓溪
,
徐世珍
液晶与显示
doi:10.3969/j.issn.1007-2780.2004.06.005
报道了在室温下用荧光光谱仪和飞秒脉冲激光激发诱导光致发光,获得氧化锌纳米颗粒(平均直径约为10 nm)缺陷发光光谱的实验,验证了氧化锌纳米颗粒缺陷能级的位置.锌填隙缺陷在距离导带底0.4 eV处产生浅施主能级,锌空位缺陷在价带顶0.3 eV处产生浅受主能级,氧锌替位缺陷在价带顶1.08 eV处产生深受主能级,在导带底1.56 eV处有氧空位缺陷引起的深杂质能级产生,氧填隙缺陷在价带顶1.35 eV处产生深受主能级.
关键词:
光致发光
,
飞秒激光
,
氧化锌纳米颗粒
,
缺陷
郝彦忠
,
蔡春立
功能材料
利用光电化学方法研究了聚3-己基噻吩的光电化学性质,其禁带宽度为1.89eV,同时确定了它的价带位置(-3.6eV)、导带位置(-5.4eV).研究发现聚3-己基噻吩属于直接跃迁型半导体,在本文条件下得到的最高IPCE值达5.2%
关键词:
聚3-己基噻吩
,
光电化学
,
导电聚合物
