Li、N不同摻雜構(gòu)型對ZnO光電特性影響的研究
發(fā)布時間：2019-04-12 09:17
【摘要】：Zn O是一種新型的直接帶隙寬帶半導(dǎo)體,室溫禁帶寬度約為3.37e V,同時在室溫下具有較大的激子束縛能(60me V),可以實現(xiàn)室溫紫外激光發(fā)射。其在氣敏傳感器件、表面聲波器件、壓電器件、高溫微電子器件和透明導(dǎo)電薄膜和紫外藍(lán)光發(fā)射等方面具有良好的發(fā)展前景。本論文采用基于密度泛函理論框架下的第一性原理平面波贗勢方法,計算分析了不同雜質(zhì)結(jié)構(gòu)對Zn O的電子結(jié)構(gòu)和光學(xué)性質(zhì)的影響。主要內(nèi)容如下:1、研究Li、N不同摻雜結(jié)構(gòu)與濃度對Zn O光電特性的影響。利用第一性原理平面波超軟贗勢方法計算了摻雜前后Zn O體系的電子結(jié)構(gòu)和光學(xué)性質(zhì)變化特性,分析了摻雜對Zn O晶體結(jié)構(gòu)電子結(jié)構(gòu)和光學(xué)性質(zhì)的影響。計算了本征Zn O和li、N不同摻雜結(jié)構(gòu)對Zn O的晶格常數(shù)、能帶結(jié)構(gòu)、電子態(tài)密度、介電函數(shù)、吸收系數(shù)的影響。結(jié)果表明:隨著Li、N原子的摻入,體系的晶格常數(shù)略微變大,鍵長變長,體系的體積增大,系統(tǒng)的形成能為負(fù)值,體系穩(wěn)定。費米能級進(jìn)入價帶,產(chǎn)生了空穴載流子,使得體系呈P型。但是在四受主摻雜中,兩個Li-N缺陷均平行C軸且相鄰的情況下,摻雜體系卻顯現(xiàn)出N型半導(dǎo)體特性。在高濃度摻雜中結(jié)構(gòu)k(Li-2N缺陷的相鄰位置出現(xiàn)一個Li-N不平行C軸的缺陷),體系也呈現(xiàn)N型特性,且結(jié)構(gòu)的形成能相當(dāng)?shù)汀Ｕf明雜質(zhì)原子之間的作用會降低體系的形成能,形成施主補償。結(jié)構(gòu)l(Li-2N和不相鄰的Li-N平行C軸),m(包含兩個不相鄰的Li-2N)缺陷的形成能為正值,說明過高濃度的摻雜不可行。2、M2-2N模型的電子結(jié)構(gòu)。本文構(gòu)建了M2-2N模型(M為與N共摻雜的Na、K、Ca、Cu、Mg、Al等原子),并對其電子結(jié)構(gòu)進(jìn)行了研究。計算結(jié)果表明Li2-N2摻雜模型的形成能低且呈現(xiàn)N型。通過對比分析,發(fā)現(xiàn)Na、K等原子與N共摻雜后體系呈現(xiàn)N型特性,而當(dāng)M為Ag、Ba、Mg原子時摻雜體系呈現(xiàn)P型特性。電荷差分態(tài)密度顯示Li、Na、K與N共摻雜時,N與N原子之間會形成共價鍵。本文計算結(jié)果為摻雜Zn O光電材料的設(shè)計與應(yīng)用提供了理論參考,對新型光電材料與器件研發(fā)有著積極的意義。
[Abstract]:Zn O is a new type of direct band gap broadband semiconductor with a band gap of about 3.37eV at room temperature and a large exciton binding energy (60me V),) at room temperature. It has a good prospect in gas sensing devices, surface acoustic devices, piezoelectric devices, high temperature microelectronic devices, transparent conductive thin films and UV blue light emission. In this paper, the influence of different impurity structures on the electronic structure and optical properties of Zn O is calculated and analyzed by using the first-principle plane wave pseudopotential method based on density functional theory (DFT). The main contents are as follows: 1. The effects of different doping structures and concentrations of Li,N on the photoelectric properties of Zn O are studied. The electronic structure and optical properties of Zn-O system before and after doping have been calculated by using the first-principle plane wave ultra-soft pseudopotential method, and the effects of doping on the electronic structure and optical properties of Zn-O crystal have been analyzed. The effects of intrinsic Zn O and li,N doping structures on the lattice constant, band structure, electron density of state, dielectric function and absorption coefficient of Zn O were calculated. The results show that with the addition of Li,N atoms, the lattice constant of the system increases slightly, the bond length becomes longer, the volume of the system increases, the formation energy of the system is negative, and the system is stable. The Fermi energy level enters the valence band, resulting in a hole carrier, which makes the system P-type. However, in the case of four-acceptor doping, two Li-N defects are parallel to the C-axis and adjacent to each other, but the doping system exhibits N-type semiconductor characteristics. In the high concentration doping, the structure k (a defect in the adjacent position of the Li-2N defect is not parallel to the C axis of Li-N), the system also presents the N-type characteristics, and the formation energy of the structure is quite low. It shows that the interaction between impurity atoms will reduce the formation energy of the system and form donor compensation. The formation energy of structural l (Li-2N and non-adjacent Li-N parallel C-axis), m (contains two non-adjacent Li-2N) defects is positive, which indicates that excessive high concentration doping is not feasible. 2, the electronic structure of M2 + 2N model. In this paper, the M _ (2) O _ (2) N model (M is an Na,K,Ca,Cu,Mg,Al atom codoped with N) has been constructed and its electronic structure has been studied. The calculated results show that the formation energy of the Li2-N2 doping model is low and it is N-type. Through comparative analysis, it is found that the co-doped system of Na,K and N presents N-type, while the doped system shows P-type when M is Ag,Ba,Mg atom. The charge difference density of states shows that the covalent bond between N and N atoms will be formed when Li,Na,K codoped with N. The calculation results in this paper provide a theoretical reference for the design and application of doped Zn O photoelectric materials, and have a positive significance for the research and development of new photoelectric materials and devices.
【學(xué)位授予單位】：中國礦業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN304.2;O483
本文編號：2456896
[Abstract]:Zn O is a new type of direct band gap broadband semiconductor with a band gap of about 3.37eV at room temperature and a large exciton binding energy (60me V),) at room temperature. It has a good prospect in gas sensing devices, surface acoustic devices, piezoelectric devices, high temperature microelectronic devices, transparent conductive thin films and UV blue light emission. In this paper, the influence of different impurity structures on the electronic structure and optical properties of Zn O is calculated and analyzed by using the first-principle plane wave pseudopotential method based on density functional theory (DFT). The main contents are as follows: 1. The effects of different doping structures and concentrations of Li,N on the photoelectric properties of Zn O are studied. The electronic structure and optical properties of Zn-O system before and after doping have been calculated by using the first-principle plane wave ultra-soft pseudopotential method, and the effects of doping on the electronic structure and optical properties of Zn-O crystal have been analyzed. The effects of intrinsic Zn O and li,N doping structures on the lattice constant, band structure, electron density of state, dielectric function and absorption coefficient of Zn O were calculated. The results show that with the addition of Li,N atoms, the lattice constant of the system increases slightly, the bond length becomes longer, the volume of the system increases, the formation energy of the system is negative, and the system is stable. The Fermi energy level enters the valence band, resulting in a hole carrier, which makes the system P-type. However, in the case of four-acceptor doping, two Li-N defects are parallel to the C-axis and adjacent to each other, but the doping system exhibits N-type semiconductor characteristics. In the high concentration doping, the structure k (a defect in the adjacent position of the Li-2N defect is not parallel to the C axis of Li-N), the system also presents the N-type characteristics, and the formation energy of the structure is quite low. It shows that the interaction between impurity atoms will reduce the formation energy of the system and form donor compensation. The formation energy of structural l (Li-2N and non-adjacent Li-N parallel C-axis), m (contains two non-adjacent Li-2N) defects is positive, which indicates that excessive high concentration doping is not feasible. 2, the electronic structure of M2 + 2N model. In this paper, the M _ (2) O _ (2) N model (M is an Na,K,Ca,Cu,Mg,Al atom codoped with N) has been constructed and its electronic structure has been studied. The calculated results show that the formation energy of the Li2-N2 doping model is low and it is N-type. Through comparative analysis, it is found that the co-doped system of Na,K and N presents N-type, while the doped system shows P-type when M is Ag,Ba,Mg atom. The charge difference density of states shows that the covalent bond between N and N atoms will be formed when Li,Na,K codoped with N. The calculation results in this paper provide a theoretical reference for the design and application of doped Zn O photoelectric materials, and have a positive significance for the research and development of new photoelectric materials and devices.
【學(xué)位授予單位】：中國礦業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN304.2;O483
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