National Renewable Energy Laboratory, Golden, Colorado 80401, USA.
Phys Rev Lett. 2013 Oct 4;111(14):145502. doi: 10.1103/PhysRevLett.111.145502. Epub 2013 Oct 2.
The use of newly discovered silicene for various optoelectronic applications depends largely on the possibility of controlling its electronic properties by chemical functionalization. To investigate this possibility, we systemically study the structural and electronic properties of chemically functionalized silicene by employing first-principles calculations combined with the cluster expansion approach. Interestingly, we find that chemically functionalized epitaxial silicene is generally accompanied by a spontaneous structural transition, which originates from the preference of sp(3) hybridization of silicon. To realized continuously tunable band gaps, chemical functionalization of freestanding silicene at ~900 K is proposed. Finally, we predict that metastable silicene can also be used as an important host material to produce novel functional materials via substitutional doping. For example, the discovered ordered Si(8)P(4) could be a strong candidate for thin-film solar cell absorbers beyond bulk Si.
新型硅烯在各种光电子应用中的使用在很大程度上取决于通过化学功能化来控制其电子性质的可能性。为了研究这种可能性，我们通过使用第一性原理计算结合团簇展开方法系统地研究了化学功能化硅烯的结构和电子性质。有趣的是，我们发现化学功能化外延硅烯通常伴随着自发的结构转变，这源于硅的 sp(3)杂化的偏好。为了实现连续可调的带隙，我们提出了在~900 K 下对自由站立硅烯进行化学功能化。最后，我们预测亚稳态硅烯也可以用作重要的主体材料，通过取代掺杂来产生新型功能材料。例如，所发现的有序 Si(8)P(4)可能是超越体硅的薄膜太阳能电池吸收体的一个强有力的候选者。
