Alessi Bruno, Macias-Montero Manuel, Maddi Chiranjeevi, Maguire Paul, Svrcek Vladimir, Mariotti Davide
Nanotechnology and Integrated Bio-Engineering Centre (NIBEC), Ulster University, Newtownabbey, BT37 0QB, UK.
Faraday Discuss. 2020 Jun 19;222(0):390-404. doi: 10.1039/c9fd00103d.
The relationship between the crystallization process and opto-electronic properties of silicon quantum dots (Si QDs) synthesized by atmospheric pressure plasmas (APPs) is studied in this work. The synthesis of Si QDs is carried out by flowing silane as a gas precursor in a plasma confined to a submillimeter space. Experimental conditions are adjusted to propitiate the crystallization of the Si QDs and produce QDs with both amorphous and crystalline character. In all cases, the Si QDs present a well-defined mean particle size in the range of 1.5-5.5 nm. Si QDs present optical bandgaps between 2.3 eV and 2.5 eV, which are affected by quantum confinement. Plasma parameters evaluated using optical emission spectroscopy are then used as inputs for a collisional plasma model, whose calculations yield the surface temperature of the Si QDs within the plasma, justifying the crystallization behavior under certain experimental conditions. We measure the ultraviolet-visible optical properties and electronic properties through various techniques, build an energy level diagram for the valence electrons region as a function of the crystallinity of the QDs, and finally discuss the integration of these as active layers of all-inorganic solar cells.
本工作研究了通过大气压等离子体（APP）合成的硅量子点（Si QD）的结晶过程与光电性质之间的关系。Si QD的合成是通过将硅烷作为气体前驱体通入限制在亚毫米空间的等离子体中来进行的。调整实验条件以促进Si QD的结晶，并制备出具有非晶和晶体特性的量子点。在所有情况下，Si QD的平均粒径在1.5 - 5.5 nm范围内明确界定。Si QD的光学带隙在2.3 eV至2.5 eV之间，受量子限制影响。然后，使用光发射光谱评估的等离子体参数被用作碰撞等离子体模型的输入，该模型的计算得出了等离子体内Si QD的表面温度，解释了在某些实验条件下的结晶行为。我们通过各种技术测量紫外 - 可见光学性质和电子性质，构建了价电子区域的能级图作为量子点结晶度的函数，最后讨论了将这些作为全无机太阳能电池活性层的集成情况。
