Ⅳ-Ⅵ族硫族化合物層狀半導(dǎo)體及其異質(zhì)結(jié)構(gòu)的第一性原理研究
發(fā)布時(shí)間：2019-05-08 08:45
【摘要】：低維納米材料由于其新穎的物理化學(xué)性質(zhì)和在多個(gè)領(lǐng)域都有很好的潛在應(yīng)用而成為了當(dāng)今納米材料研究的前沿和熱點(diǎn),對(duì)能源、信息等領(lǐng)域有著越來(lái)越深遠(yuǎn)的影響�；诘谝恍栽淼拿芏确汉碚�(density functional theory,DFT)在納米材料的微觀設(shè)計(jì)和性能預(yù)測(cè)方面是應(yīng)用非常廣泛而且行之有效的方法。本論文即是利用DFT對(duì)IV-VI族硫族化合物層狀半導(dǎo)體及其異質(zhì)結(jié)構(gòu)進(jìn)行系統(tǒng)的研究。首先,我們研究了SnSe2和SnS2形成的固熔體異質(zhì)結(jié)構(gòu),并從其穩(wěn)定性、電子結(jié)構(gòu)和光學(xué)性質(zhì)及其調(diào)制等方面進(jìn)行了具體和系統(tǒng)的研究。其次,我們探討了類黑磷材料MXs(M=Sn,Ge;X=Se,S)的性質(zhì),并重點(diǎn)討論了層數(shù)對(duì)這些性質(zhì)的影響;最后,根據(jù)能帶帶邊對(duì)齊的計(jì)算,探討了類黑磷材料相互之間以及黑磷與類黑磷材料之間形成II-型異質(zhì)結(jié)構(gòu)的可能性,并進(jìn)一步提出通過(guò)改變層數(shù),可以實(shí)現(xiàn)II-I以及I-II型異質(zhì)結(jié)構(gòu)的轉(zhuǎn)變。本論文一共分為六個(gè)章節(jié),第一章主要介紹了IV-VI族硫族化合物層狀結(jié)構(gòu)材料的研究現(xiàn)狀以及本論文的研究背景、研究目標(biāo)和研究?jī)?nèi)容。第二章簡(jiǎn)要的闡述了密度泛函理論以及第一性原理計(jì)算所需要的VASP軟件包。第三章中我們對(duì)SnSe2(1-x)S2x合金的穩(wěn)定性、電子結(jié)構(gòu)和光學(xué)性質(zhì)做了系統(tǒng)性地研究。我們發(fā)現(xiàn)SnSe2和SnS2在溫度高于702K時(shí)能形成“隨機(jī)”合金,且上下層硫原子摻雜數(shù)目趨向于相同。隨著硫原子濃度的增大,合金體系的帶隙值非線性減小,且光學(xué)性質(zhì)呈現(xiàn)各向異性并在可見(jiàn)光區(qū)域合金呈現(xiàn)更為明顯的吸收峰。第四章中我們研究了MXs體相結(jié)構(gòu)以及單層、多層結(jié)構(gòu)的穩(wěn)定性、電子結(jié)構(gòu)、光學(xué)性質(zhì)和有效質(zhì)量,重點(diǎn)討論了層數(shù)對(duì)這些性質(zhì)的影響。研究發(fā)現(xiàn),隨著層數(shù)的增加,體系變得更加穩(wěn)定,帶隙值變小且與層數(shù)的倒數(shù)表現(xiàn)出極好的線性關(guān)系(GeS除外)。光學(xué)性質(zhì)研究發(fā)現(xiàn),所有的單層、多層MXs均表現(xiàn)出各向異性,特別是Sn S和Sn Se體系在可見(jiàn)光區(qū)域具有很強(qiáng)的吸收。對(duì)有效質(zhì)量的計(jì)算發(fā)現(xiàn)只有Sn S單層和多層結(jié)構(gòu)的電子有效質(zhì)量是隨著層數(shù)的增加而遞減的,其他體系沒(méi)有看到明顯的規(guī)律。在第五章中,我們先通過(guò)對(duì)MXs和磷烯的能帶帶邊位置的計(jì)算,探討了MXs相互之間以及它們與黑磷之間形成II-型異質(zhì)結(jié)構(gòu)的可能性,并進(jìn)一步研究了異質(zhì)結(jié)層依賴的電子性能。通過(guò)構(gòu)建Moiré模式,證實(shí)了可以通過(guò)改變層數(shù)來(lái)實(shí)現(xiàn)異質(zhì)結(jié)從I到II型或者II到I型的轉(zhuǎn)變。第六章是對(duì)論文的總結(jié)和展望。
[Abstract]:Because of its novel physical and chemical properties and potential applications in many fields, low-dimensional nano-materials have become the frontier and hot spot of nano-materials research, and have more and more far-reaching influence on energy, information and other fields. Density functional theory (density functional theory,DFT) based on first-principles is a widely used and effective method in micro-design and performance prediction of nano-materials. In this thesis, DFT is used to systematically study the layered semiconductor and its heterostructure of IV-VI chalcogenide compounds. Firstly, the solid melt heterostructures formed by SnSe2 and SnS2 have been studied, and their stability, electronic structure, optical properties and modulation have been studied in detail and systematically. Secondly, we discussed the properties of black-like phosphorus-like material MXs (M-Si-Sn, GE-X-se, S), and discussed the influence of layers on these properties. Finally, according to the calculation of band edge alignment, the possibility of forming II- heterostructure between black phosphorus-like materials and black phosphorus-like materials is discussed, and it is further suggested that the layer number can be changed by changing the number of layers. The transformation of II-I and I-II heterostructure can be realized. This thesis is divided into six chapters. The first chapter mainly introduces the research status of IV-VI chalcogenide layered structure materials, the research background, the research goal and the research content of this thesis. In chapter 2, the density functional theory (DFT) and the VASP software package for first-principle calculation are briefly described. In chapter 3, we systematically study the stability, electronic structure and optical properties of SnSe2 (1 x) S 2x alloy. It is found that SnSe2 and SnS2 can form "random" alloys at temperatures higher than 702K, and the doping number of sulfur atoms in the upper and lower layers tends to be the same. With the increase of sulfur atom concentration, the band gap value of the alloy system decreases non-linearly, and the optical properties of the alloy show anisotropy and a more obvious absorption peak in the visible light region. In chapter 4, we study the stability, electronic structure, optical properties and effective mass of the bulk phase structure and monolayer and multilayer structure of MXs, and discuss the influence of the number of layers on these properties. It is found that with the increase of the number of layers, the system becomes more stable, and the band gap becomes smaller and has a good linear relationship with the reciprocal of the layers (except GeS). It is found that all monolayer and multilayer MXs exhibit anisotropy, especially the Sn S and Sn Se systems have strong absorption in the visible region. It is found that the electron effective mass of only Sn S monolayer and multilayer structure decreases with the increase of the number of layers, but no obvious rule is found in other systems. In chapter 5, by calculating the band edge positions of MXs and phosphene, we discuss the possibility of forming II- type heterostructures between MXs and phosphene, and further study the electronic properties of heterojunction layer dependence. By constructing Moir 茅 model, it is proved that the transformation of heterojunction from type I to type II or from II to type I can be achieved by changing the number of layers. The sixth chapter is the summary and prospect of the thesis.
【學(xué)位授予單位】：安徽師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB383.1
本文編號(hào)：2471770
[Abstract]:Because of its novel physical and chemical properties and potential applications in many fields, low-dimensional nano-materials have become the frontier and hot spot of nano-materials research, and have more and more far-reaching influence on energy, information and other fields. Density functional theory (density functional theory,DFT) based on first-principles is a widely used and effective method in micro-design and performance prediction of nano-materials. In this thesis, DFT is used to systematically study the layered semiconductor and its heterostructure of IV-VI chalcogenide compounds. Firstly, the solid melt heterostructures formed by SnSe2 and SnS2 have been studied, and their stability, electronic structure, optical properties and modulation have been studied in detail and systematically. Secondly, we discussed the properties of black-like phosphorus-like material MXs (M-Si-Sn, GE-X-se, S), and discussed the influence of layers on these properties. Finally, according to the calculation of band edge alignment, the possibility of forming II- heterostructure between black phosphorus-like materials and black phosphorus-like materials is discussed, and it is further suggested that the layer number can be changed by changing the number of layers. The transformation of II-I and I-II heterostructure can be realized. This thesis is divided into six chapters. The first chapter mainly introduces the research status of IV-VI chalcogenide layered structure materials, the research background, the research goal and the research content of this thesis. In chapter 2, the density functional theory (DFT) and the VASP software package for first-principle calculation are briefly described. In chapter 3, we systematically study the stability, electronic structure and optical properties of SnSe2 (1 x) S 2x alloy. It is found that SnSe2 and SnS2 can form "random" alloys at temperatures higher than 702K, and the doping number of sulfur atoms in the upper and lower layers tends to be the same. With the increase of sulfur atom concentration, the band gap value of the alloy system decreases non-linearly, and the optical properties of the alloy show anisotropy and a more obvious absorption peak in the visible light region. In chapter 4, we study the stability, electronic structure, optical properties and effective mass of the bulk phase structure and monolayer and multilayer structure of MXs, and discuss the influence of the number of layers on these properties. It is found that with the increase of the number of layers, the system becomes more stable, and the band gap becomes smaller and has a good linear relationship with the reciprocal of the layers (except GeS). It is found that all monolayer and multilayer MXs exhibit anisotropy, especially the Sn S and Sn Se systems have strong absorption in the visible region. It is found that the electron effective mass of only Sn S monolayer and multilayer structure decreases with the increase of the number of layers, but no obvious rule is found in other systems. In chapter 5, by calculating the band edge positions of MXs and phosphene, we discuss the possibility of forming II- type heterostructures between MXs and phosphene, and further study the electronic properties of heterojunction layer dependence. By constructing Moir 茅 model, it is proved that the transformation of heterojunction from type I to type II or from II to type I can be achieved by changing the number of layers. The sixth chapter is the summary and prospect of the thesis.
【學(xué)位授予單位】：安徽師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB383.1
【參考文獻(xiàn)】
相關(guān)期刊論文 前1條
1 張勝利;劉尚果;黃世萍;蔡波;謝美秋;渠莉華;鄒友生;胡自玉;余學(xué)超;曾海波;;單層硒化鍺多形體的結(jié)構(gòu)特性和電子性質(zhì)（英文）[J];Science China Materials;2015年12期
，本文編號(hào)：2471770
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