个人信息Personal Information
研究员
博士生导师
硕士生导师
性别:男
毕业院校:东北师范大学
学位:学士
所在单位:电子信息与电气工程学部
电子邮箱:nhwang@dlut.edu.cn
Surface exciton emission of MgO crystals
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论文类型:期刊论文
发表时间:2013-09-11
发表刊物:JOURNAL OF PHYSICS D-APPLIED PHYSICS
收录刊物:SCIE、EI、Scopus
卷号:46
期号:36
ISSN号:0022-3727
摘要:MgO crystals have been exposed to vacuum ultraviolet (VUV) radiation from a synchrotron, with energies up to 9 eV, and the emitted light, at wavelengths above 200 nm, was observed. It is concluded that bulk excitons, play an important role in the diffusion of energy inside MgO crystals, resulting in 5.85 eV (212 nm) emission from the MgO terraces of large (0.2-2 mu m) MgO: F crystals. In the case of aliovalent impurity doping, then the bulk exciton energy is also transferred to the V-k centres and 5.3 eV (235 nm) light is emitted. Both fluorine and silicon doping appear to promote UV surface emission, acting similarly to an ns2 ion inside MgO, while strong scandium doping is killing the surface emission completely. The 212 nm surface UV emission and the 235 nm bulk UV emission can be excited only at the bandgap edge. Broadband visible light, centred around 400 nm, is also emitted. Contrary to the UV emission, this is not generated when excited at the bandgap edge; instead, we find that it is only excited at sub-bandgap energies, with a maximum at the 5C surface excitation energy of 5.71 eV (217 nm) for the MgO terraces.