錳摻雜單層二維量子結構半導體之合成、鑑定及應用

Abstract

本研究探討單層二維奈米片材料摻雜二價錳離子後之磁光特性，單層二維奈米片之化學實驗式分別為MnxCd1-xSe(en)0.5和MnxZn1-xSe(en)0.5，以乙二胺(ethylenediamine)作為層與層之橋接。半導體之合成方式採用溶劑熱條件，以硼氫化鈉還原硒粉做為硒的前驅物，透過合成溫度的調控，優化奈米片生長條件。可調控的二價錳離子濃度(x=0~12 %) 摻雜入單層二維奈米片MnxCd1-xSe(en)0.5和MnxZn1-xSe(en)0.5分別產生晶格收縮與擴張的改變，受到錳d軌域上的五個為成對電子，伴隨著磷光的發生。經由元素分析與X光光電子能譜發現在合成過程會吸附氧並產生鍵結，造成鍵結能受不同摻雜濃度錳離子而改變。摻雜錳單層二維奈米片在電子順磁共振光譜方向性測量中表現出各項異性，且在低溫下的光譜經擬合出大的零場分裂值 (D =3850 MHz)。在磁圓二色性光譜在室溫下，量測到很大塞曼分裂與朗克g因子 (g= 200~300)，指出在單層二為材料具有很強的sp-d交互作用力。在具有原子級厚度的單層二維半導體，表現強量子侷限效應，並發現在室溫下有良好的性質，未來在自旋電子學的應用有更好的發展。

This study investigates the magneto-optical properties of single-layer two-dimensional nanosheets doped with divalent manganese ions. The chemical experimental formulas of single-layer two-dimensional nanosheets are MnxCd1-xSe(en)0.5 and MnxZn1-xSe(en)0.5, using ethylenediamine as the layer-to-layer bridge. The semiconductor synthesis method uses solvothermal conditions, using sodium borohydride to reduce selenium powder as the precursor of selenium, and optimizes the growth conditions of the nanosheets through the control of the synthesis temperature. Tunable amounts of Mn2+ (x=0~12%) doping into single-layer two-dimensional nanosheets MnxCd1-xSe(en)0.5 and MnxZn1-xSe(en)0.5 change the lattice contraction and expansion, respectively. The five unpaired electrons on the d orbital of manganese, accompanied by the occurrence of phosphorescence. Through elemental analysis and X-ray photoelectron spectroscopy, it is found that oxygen will be adsorbed and bonding will occur during the synthesis process, resulting in the bonding energy being changed by different doping concentrations of manganese ions. The doped manganese single-layer two-dimensional nanosheets show anisotropy in the directionality measurement of electron paramagnetic resonance spectroscopy, and the spectrum at low temperature has been fitted to a large zero-field splitting value (D = 3850 MHz). In the magnetic circular dichroism spectrum at room temperature, a large Zeeman splitting and Longk g factor (g=200~300) were measured, indicating that the material in the monolayer has a strong sp-d interaction force. In a single-layer two-dimensional semiconductor with atomic-level thickness, it exhibits strong quantum confinement effects, and has been found to have good properties at room temperature, and the application of spintronics will have better development in the future.