本文關(guān)鍵詞：類石墨烯低維材料邊緣修飾和表面吸附的第一性原理研究　出處：《北方工業(yè)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 第一性原理 BC_2N納米帶 邊緣修飾 藍磷烯 表面吸附 氣體傳感器

【摘要】：低維納米材料具有不同于傳統(tǒng)塊體材料的新穎的物理化學(xué)性質(zhì),使其在電子、光電子、電化學(xué)、氣體傳感器和生物等領(lǐng)域都有著非常高的應(yīng)用前景。近年來,隨著計算機處理性能飛躍式的進步以及計算理論的不斷完善,采用理論模型和第一性原理計算方法對實驗現(xiàn)象進行合理解釋或預(yù)測納米材料以及電子元器件的性能已逐漸成為主流。本論文系統(tǒng)地研究了邊緣修飾對鋸齒形BC_2N納米帶結(jié)構(gòu)、電子結(jié)構(gòu)、磁性性質(zhì)的影響和藍磷烯對氣體分子的吸附性能以及氣體傳感特性,所采用的研究方法是基于密度泛函理論和非平衡格林函數(shù)的第一性原理計算方法。全文共分為五章:第一章中,介紹了低維納米材料的性質(zhì)、研究背景以及最新的科研進展,詳細介紹了本論文中所研究的鋸齒形BC_2N納米帶和藍磷烯的結(jié)構(gòu)特征、電磁性能、輸運性能、實驗制備以及可能的應(yīng)用方向等相關(guān)的研究背景。第二章中,介紹了基于密度泛函理論和非平衡函數(shù)的第一原理計算方法及第一性原理計算軟件。第三章中,我們采用H,F,Cl,OH,O,S和Se七種常見的非金屬原子和分子對鋸齒形BC_2N納米帶進行邊緣修飾,系統(tǒng)地研究了不同的邊緣修飾位置和條帶寬度對BC_2N納米帶的結(jié)構(gòu)、穩(wěn)定性、電子結(jié)構(gòu)和磁性性質(zhì)的影響。研究結(jié)果表明:邊緣狀態(tài)和納米帶寬度對于一維納米帶材料的結(jié)構(gòu)和電磁性質(zhì)有較大程度的影響;使用不同原子或分子修飾后的納米帶呈現(xiàn)出不同的電磁特性,其中使用O原子修飾后的納米帶呈現(xiàn)出鐵磁性的基態(tài);增加納米帶寬度將會使整個體系的結(jié)合能負值均增大,穩(wěn)定性增強;半導(dǎo)體性的納米帶的能隙大小隨著寬度的增加而減少,當寬度足夠大時,使用OH,F原子修飾后的納米帶和邊緣裸露的納米帶的能隙逐漸消失,而使用H原子修飾的納米帶則表現(xiàn)出半極金屬(half-metal)的特性。在第四章,我們選取七種氣體分子(CO,CO_2,NO,NO_2,NH_3,SO_2和H_2S)作為吸附分子,研究了吸附后藍磷烯的結(jié)構(gòu)、穩(wěn)定性、電磁性質(zhì)和輸運性能的變化。研究結(jié)果表明:選取的七種氣體分子均是以物理吸附的形式吸附在藍磷烯基體的表面;吸附氣體分子后的藍磷烯結(jié)構(gòu)沒有發(fā)生大的變形,說明吸附后的體系比較穩(wěn)定。通過計算吸附后的基態(tài)和能帶結(jié)構(gòu),我們發(fā)現(xiàn)吸附后的藍磷烯依然保持著半導(dǎo)體的能隙,NO和NO_2分子吸附后體系呈現(xiàn)鐵磁性的基態(tài),磁矩為1.0μB。輸運性能的計算中,我們發(fā)現(xiàn)吸附氣體分子后藍磷烯的輸運電流發(fā)生了不同程度的改變,表現(xiàn)出較大的敏感度,這將為新型高性能的氣體吸附傳感器材料提供一種新的研究方向。在最后一章,對于本論文中的所做的研究工作進行了總結(jié)概括,并對后續(xù)的科研工作和方向進行了展望。
[Abstract]:Low-dimensional nanomaterials have novel physical and chemical properties different from those of traditional bulk materials, which make them have high application prospects in the fields of electronics, photoelectron, electrochemistry, gas sensors and biology. With the development of computer processing performance and the improvement of computing theory. The theoretical model and first-principle calculation method are used to explain or predict the experimental phenomena reasonably. The performance of nano-materials and electronic components has gradually become the mainstream. In this paper, the effect of edge modification on serrated B has been systematically studied. Structure of C2N nanobelts. The effects of electronic structure, magnetic properties, adsorption properties of blue phosphorus on gas molecules and gas sensing properties. The research method is based on the density functional theory and the first principle calculation method of non-equilibrium Green's function. The thesis is divided into five chapters: in chapter 1, the properties of low-dimensional nanomaterials are introduced. In this paper, the structure characteristics, electromagnetic properties and transport properties of serrated BC_2N nanobelts and blue-phosphorylenes are introduced in detail. In the second chapter, the first principle calculation method based on density functional theory and non-equilibrium function and the first principle calculation software are introduced. We used seven common nonmetallic atoms and molecules of BC_2N nanobelts, named Hedgehos and se, to modify the edge of the serrated BC_2N nanobelts. The structure and stability of BC_2N nanobelts with different edge modification positions and band width were studied systematically. The influence of electronic structure and magnetic properties. The results show that the edge state and the width of nanobelts have great influence on the structure and electromagnetic properties of one-dimensional nanobelts. The nanobelts modified by different atoms or molecules exhibit different electromagnetic properties, and the nanobelts modified by O atoms exhibit ferromagnetic ground state. Increasing the width of nanobelts will increase the negative binding energy and increase the stability of the whole system. The band gap of semiconductor nanobelts decreases with the increase of width. When the width is large enough, the gap of nanobelts modified with OHF atoms and those with bare edges gradually disappear. In Chapter 4th, we selected seven kinds of gas molecules, COCO2NOS-NOS2. As adsorption molecules, the structure and stability of cyanophosphorene after adsorption were studied. The results show that the selected seven kinds of gas molecules are physically adsorbed on the surface of blue phosphene matrix. The structure of the adsorbed gas molecule did not deform, which indicated that the adsorbed system was stable. The ground state and band structure of the adsorbed system were calculated. It is found that the adsorbed blue-phosphorylenes still maintain the band-gap no and the NO_2 molecule adsorbed with ferromagnetic ground state, and the magnetic moment is 1.0 渭 B. the transport properties of the system are calculated. We found that the transport current of blue-phosphorylenes changed in varying degrees after the adsorption of gas molecules, showing a greater sensitivity. This will provide a new research direction for the new high-performance gas adsorption sensor materials. In the last chapter, the research work done in this paper is summarized. The future research work and direction are prospected.
【學(xué)位授予單位】：北方工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TB383.1;O647.3

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