钴掺杂硒化锌微纳结构中的发光行为

Luminescence Behavior of Cobalt-Doped ZnSe Micro-Nanostructures

微区光致发光光谱技术是研究稀磁半导体材料中激子与磁性离子之间相互作用的一种重要方法。通过化学气相沉积法合成了高质量钴离子(Ⅱ)掺杂硒化锌(ZnSe)微纳结构,并通过微区光致发光光谱表征了单个纳米片的带边发光。测试结果表明,Co(Ⅱ)掺杂ZnSe纳米片的带边激光发射峰位在2.77eV,高于室温下闪锌矿结构的ZnSe带边发光2.67eV,证实了该纳米片中同时存在纤锌矿和闪锌矿两种结构。分析发现,纤锌矿结构的Co(Ⅱ)掺杂ZnSe纳米片相比稳定的闪锌矿结构的带边激子态能量更高,并且可产生独自的发光。通过低温下的稳态光谱研究发现,在77K下,可以同时观察到激子、束缚激子和激子磁极化子(EMP)的发光特征。激子磁极化子的发光结果证明,在Co(Ⅱ)掺杂ZnSe纳米片的稀磁半导体体系中可实现玻色子激光的发射,为未来自旋电子器件、光致磁性等技术的发展应用提供了思路。

Micro-photoluminescence(micro-PL)spectrum is an important method to study the interaction between excitons and magnetic ions in diluted magnetic semiconductor materials.High quality Co(Ⅱ)doped zinc selenide(ZnSe)nanostructures were synthesized by chemical vapor deposition method and the band edge luminescence of individual nanosheet was characterized by micro-PL spectra.The test results show that the band edge laser emission peak of Co(Ⅱ)doped ZnSe nanosheet is at 2.77 eV,which is higher than that of ZnSe nanosheets with zinc blende structure at room temperature(2.67 eV),indicating the coexistence of both wurtzite and zinc blende structures in the nanosheets.It is found that the Co(Ⅱ)doped ZnSenanosheets with wurtzite structure have higher exciton state energy at the band edge than those with stable zinc blende structure and can produce independent luminescence.Meanwhile,it is found that the luminescence characteristics of exciton,bound exciton and exciton magnetic polaron(EMP)were observed simultaneously at 77 K by steady-state spectra at low temperature.The luminescence results of the EMP show that the emission of boson laser can be realized in Co(Ⅱ)doped ZnSe nanosheets in diluted magnetic semiconductor system,which provides a new idea for the development and application of spintronic devices and photon induced magnetism in the future.