纳米硅量子点中磷硼共掺及相关新颖光电性质研究

Doping plays a key role in semiconductors for device applications. With the applications of nanocrystalline Si quantum dots in the next generation nano-electronic and opto-electronic devices, it becomes more and more important to understand the doping effect and behaviors of dopants in them. Based on our previous work, we found the different doping behaviors in nc-Si between the P and B impurities which is also quite different from the doping effect in bulk Si. Here, we propose to modify the electronic structures and interface (or surface) states of nc-Si by P/B co-doping based on the fabrication of P/B-co-doped nc-Si materials. We will study the novel properties caused by the co-doping, especially the influences of co-doping on the conduction type and conductivity as well as the carrier transport process in nc-Si system, we will try to improve the P doping efficiency by B co-doping at the suitable parameters. Meanwhile, we will study the localized surface plasmon resonance effect due to the doping in nc-Si and the possibility to modulate the related effect by co-doping. We will develop the way to enhance the interesting sub-band luminescence efficiency in doped nano-Si-based multilayered structures and explore the possibility of P-induced deep level to achieve sub-band light emission and passivation effect of B co-doping on the non-radiative recombination centers. We hope to further understand the distribution of dopants, doping effect nc-Si and give the deep insight into the influences of various dopants on on the electronic structures and physical properties, which will provide the solid basis to develop new type nano-electronic and opto-electronic devices based on nano-Si.

掺杂是半导体材料能在器件中应用的关键，由于在纳米尺度下对硅量子点的掺杂效应与体材料有很大的不同，因此对其的研究具有重要的科学意义。在先前的研究中，我们发现磷(P)和硼(B)在纳米硅量子点中具有不同的掺杂行为，基于此，本课题提出了在纳米硅量子点中利用P/B共掺来调节纳米硅量子点的电子结构和界面（表面）特性，研究在纳米硅中由于共掺所导致的新颖光电性质，特别是共掺对纳米硅的导电特性和输运性质的影响，利用合适的共掺提高磷在纳米硅中的掺杂效率；研究由于掺杂导致的局域表面等离激元效应以及利用共掺对其进行调控的可能性；探索利用P/B共掺抑制非辐射复合过程以实现磷掺杂纳米硅量子点的亚带隙发光的增强。通过本课题的研究，将有助于进一步理解在纳米硅量子点中杂质特性及相关的掺杂效应，解决在纳米硅量子点中的掺杂及掺杂对材料的电子结构和光电特性的影响等关键科学问题，为实现新一代的纳米硅基电子和光电子器件打下基础。

本项目是针对掺杂纳米硅量子点中杂质特性及相关的掺杂效应，特别是掺杂对材料的电子结构和光电特性的影响等关键科学问题而进行的。主要研究内容包括：利用当今成熟的微电子工艺技术，结合硅基光子学技术与纳米技术，研究如何实现对纳米硅量子点的可控制备、均匀掺杂及器件应用。研究了纳米硅量子点中磷、硼杂质在原子尺度上的空间位置分布与行为表现特征；研究了掺杂对纳米硅量子点的电子结构与光电特性的影响，特别是磷/硼共掺杂下纳米硅量子点亚带隙发光增强的物理机制。同时，基于制备出的掺杂纳米硅量子点材料，构建了p-i-n型太阳电池器件；进一步，将其与硅纳米线阵列结构结合，构建了纳米硅量子点/硅纳米线异质结太阳能电池器件，研究了器件的光伏特性及器件性能提高的可能途径。研究成果受到国际同行关注，应邀在J. Phys. D: Appl. Phys.和《半导体学报》上发表了关于纳米硅以及掺杂效应的综述论文，并在多个国际学术会议上作邀请报告。