本文選題：低維半導(dǎo)體納米材料 + 熱導(dǎo)率��； 參考：《上海師范大學(xué)》2017年碩士論文

【摘要】：隨著納米技術(shù)的不斷發(fā)展,低維半導(dǎo)體納米材料將對人們的生活產(chǎn)生重大影響。低維半導(dǎo)體納米材料在電子、光學(xué)、熱力學(xué)、機(jī)械以及化學(xué)上有著優(yōu)異的特性,表現(xiàn)出了其所對應(yīng)的塊體材料所不具備的物理化學(xué)性質(zhì)。對它們的功能性質(zhì)的調(diào)制可以促進(jìn)新型半導(dǎo)體器件的開發(fā),從而推動技術(shù)的進(jìn)步。理解和控制低維功能納米材料的結(jié)構(gòu)、物性以及結(jié)構(gòu)--物性之間的關(guān)聯(lián),建立可控制備方法,對發(fā)展功能導(dǎo)向的新體系和新技術(shù)有著重要的指導(dǎo)意義。針對低維半導(dǎo)體納米材料的物理性質(zhì)及其調(diào)控的理論研究,本學(xué)位論文利用分子動力學(xué)模擬方法和基于密度泛函理論的第一性原理計算方法,分別以硒化鎘納米線、硒化鎘納米帶以及單層砷結(jié)構(gòu)為研究對象,探討了這些體系在不同調(diào)控手段下,它們物理性質(zhì)的變化,為今后低維半導(dǎo)體納米材料的實(shí)際應(yīng)用提供了重要的理論依據(jù),主要研究內(nèi)容和結(jié)果如下:(一)采用第一性原理計算方法研究了軸向應(yīng)變條件下硒化鎘納米線的電子結(jié)構(gòu)特性以及對其光學(xué)性質(zhì)的變化。結(jié)果表明,應(yīng)變作用下硒化鎘納米線的價帶部分發(fā)生了價帶頂競爭切換現(xiàn)象,且與納米線孔徑大小有一定關(guān)聯(lián)。(二)采用分子動力學(xué)模擬方法研究了不同尺寸、應(yīng)變、扭轉(zhuǎn)角度以及溫度對硒化鎘納米線熱導(dǎo)率的影響。研究結(jié)果表明,壓縮應(yīng)變能更好地降低其熱導(dǎo)率,使得熱導(dǎo)率能在更大的范圍內(nèi)變化。(三)采用第一性原理計算方法研究了外加電場對扶手型硒化鎘納米帶的能帶結(jié)構(gòu)的調(diào)制作用。通過施加橫向電場,硒化鎘納米帶的帶隙隨著場強(qiáng)的增大而逐漸減小,在一定場強(qiáng)下硒化鎘納米帶從半導(dǎo)體轉(zhuǎn)變到導(dǎo)體,其價帶頂與導(dǎo)帶底的電荷分布也隨場強(qiáng)的增強(qiáng)而重新分布并向某一端靠攏。(四)采用第一性原理法研究了應(yīng)變對單層砷結(jié)構(gòu)的力學(xué)性質(zhì)以及光學(xué)性質(zhì)的影響。單層砷結(jié)構(gòu)在橫向應(yīng)變條件下其面內(nèi)具有正泊松比,且各向異性,而在面外x方向的拉伸引起了z方向的膨脹,具有負(fù)泊松比,數(shù)值大于黑磷的負(fù)泊松比。同時,應(yīng)變也引起了單層砷結(jié)構(gòu)光學(xué)性質(zhì)的變化,且呈現(xiàn)出了各向異性行為。
[Abstract]:With the development of nanotechnology, low-dimensional semiconductor nanomaterials will have a great impact on people's lives. Low-dimensional semiconductor nanomaterials have excellent properties in electronics, optics, thermodynamics, mechanics and chemistry, showing physical and chemical properties that their corresponding bulk materials do not have. Modulation of their functional properties can promote the development of new semiconductor devices and promote the progress of technology. Understanding and controlling the relationship between structure, physical properties and structure-physical properties of low-dimensional functional nanomaterials and establishing controllable preparation methods are of great significance for the development of new functional oriented systems and new technologies. Based on the theoretical study of physical properties and regulation of low-dimensional semiconductor nanomaterials, this dissertation uses molecular dynamics simulation method and first-principle calculation method based on density functional theory, respectively, using cadmium selenide nanowires. The structure of cadmium selenide nanoribbons and monolayers as well as arsenic monolayers were studied. The changes of their physical properties under different control methods were discussed, which provided an important theoretical basis for the practical application of low-dimensional semiconductor nanomaterials in the future. The main contents and results are as follows: (1) the electronic structure and optical properties of cadmium selenide nanowires under axial strain are studied by first principle method. The results show that the valence band switching phenomenon occurs in the valence band of cadmium selenide nanowires under strain, which is related to the pore size of the nanowires. (2) the effects of different sizes, strain, torsion angle and temperature on the thermal conductivity of cadmium selenide nanowires were studied by molecular dynamics simulation. The results show that the compression strain can reduce the thermal conductivity more effectively and make the thermal conductivity change in a larger range. (3) the modulation effect of applied electric field on the band structure of the armrest type cadmium selenide nanoribbons has been studied by using the first-principle calculation method. By applying a transverse electric field, the band gap of cadmium selenide nanobelts decreases with the increase of the field strength. At a certain field strength, the band gap of CD _ 2See nanobelts changes from semiconductor to conductor. The charge distribution at the top and bottom of the valence band redistributes with the increase of the field strength and draws closer to one end. (4) the influence of strain on the mechanical and optical properties of arsenic monolayer is studied by first principle method. The monolayer arsenic structure has a positive Poisson's ratio in the plane and anisotropy under transverse strain, while the stretching in the off-plane x direction leads to the expansion in the z direction, which has a negative Poisson's ratio, which is larger than the negative Poisson's ratio of black phosphorus. At the same time, the strain also caused the change of optical properties of arsenic monolayer structure, and showed anisotropic behavior.
【學(xué)位授予單位】：上海師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN304;TB383.1

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 Chao Han;Zhen Li;Shixue Dou;;Recent progress in thermoelectric materials[J];Chinese Science Bulletin;2014年18期

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本文編號：1998889