热退火、激光束和电子束等作用对纳米硅制备及其局域态发光特性的影响

在纳米晶体硅制备的过程中, 晶化处理是影响和提高纳米硅发光效率的重要制备环节. 热退火、激光退火和电子束辐照是使纳米硅样品晶化的不同方式. 实验表明: 选取适当的晶化方式和参量对制备纳米硅晶体结构至关重要, 特别是在制备硅量子点和量子面的过程中控制好参量, 可以得到较高的发光效率. 有趣的是, 在实验中发现: 当晶化时间较短(如低于20 min)时, 可以获得较好的纳晶硅结构(如量子点结构), 对应于较好的纳晶硅光致发光(PL)和掺杂局域态发光; 当晶化时间较长(如超过30 min)时, 纳米晶体硅结构被破坏, 致使PL谱逐渐减弱与消失. 结合热退火、激光退火和电子束辐照对纳米硅晶化过程, 本文建立起晶化时间对纳米硅局域态发光影响机理的物理模型, 解释了晶化时间对纳米硅局域态发光的影响.

Effects of thermal annealing,laser and electron beam on the fabrication of nanosilicon and the emission properties of its localized states

In the process of preparing nanosilicon, the crystallization process is an important part to influence and improve the efficiency of nanosilicon luminescence. Thermal annealing, laser annealing, and electron beam irradiation are different ways of crystallizing the nanosilicon. Different photoluminescence (PL) spectra and structures of nanocrystalline silicon are observed for different treatment time of crystallization. The experimental results show that choosing an appropriate crystallization method and parameters is very important for preparing the nanosilicon crystalline structures. High luminous efficiency can be obtained by controlling the parameters properly in the processes of preparing silicon quantum dots (QDs) and quantum surface, especially. It is discovered experimentally that better nanosilicon crystalline structure such as nanosilicon QD structure, better PL luminescence, and the doped localized state luminescence of nanocrystalline silicon can be obtained when the crystallization time is about 20 min. According to the nanosilicon crystallization process under thermal annealing, laser annealing and electron beam irradiation, a physical model of the effect of crystallization time on the nanosilicon localized state luminescence is established in this paper, which can explain the effect of crystallization time on the localized state luminescence of the nanosilicon.