InGaN异质结太阳能电池中载流子输运的研究
发布时间：2018-08-25 17:25
【摘要】：随着蓝光LED的广泛使用,InGaN材料受到越来越广泛的关注。它不仅可做为发光材料,也展现了非常优异的光伏特性。由于其能带可以从0.65eV到3.4eV连续可调,几乎覆盖了整个可见光谱,并且还具有高吸收系数,高迁移率和高抗辐照能力,因此InGaN作为太阳能电池具有巨大潜力。本文对InGaN异质结太阳电池的载流子输运进行了较系统的研究。第一章主要阐述了InGaN材料应用于光伏领域的国内外研究进展,以及存在的主要问题和挑战。还介绍了本文使用的模拟系统,以及异质结太阳能电池的基础知识。第二章主要研究了不同In组分的InGaN/Ga N多量子阱太阳电池响应波长远低于吸收边的原因。我们发现低能量光子激发的载流子所能达到的能级较低,需要越过很高的势垒才能逃逸出量子阱,当激发光子能量低于一定阈值,产生的载流子只能复合而对光电流没有贡献。载流子逃逸的光子能量阈值与垒厚有关,计算得到了不同垒厚情况下InGaN/Ga N多量子阱太阳电池波长响应极限,为InGaN/GaN多量子阱太阳电池的设计提供了参考。第三章研究了V型坑在In GaN多量子阱太阳能电池中的作用。我们通过数值模拟的手段发现了V型坑能够为载流子提供输运的通道,从而可以提高转换效率。除此之外,我们对不同位错密度的V坑进行了讨论,发现V坑形成的越多对电池的提升效果越明显。第四章研究了温度对In GaN太阳能电池中载流子运输的作用,我们发现温度从室温升高到360K,光电流的增大随光源的注入电流的增大而增大,这意味着从量子阱逃逸的载流子总数也越多。并且通过量子点-量子阱复合模型很好地解释了我们的实验结果。为了得到更高的效率,我们在第五章对InGaN p-i-n型太阳能电池的异质结界面进行了优化,我们发现用n-ZnO作为电子传输层不仅能够改善晶格失配带来的极化效应,而且能够有效减少界面势垒,更有利于光生载流子的输运。同时研究了将p型GaN用p型InGaN代替能够增加吸收的光子并且改善界面的性质,能够将电池的转化效率从7%提高到14%。进一步优化器件的尺寸可以将效率提高到15%。第六章主要对前面几章的内容进行总结以及对未来应用进行了展望。
[Abstract]:With the wide use of blue LED materials, more and more attention has been paid to InGaN materials. It not only can be used as a luminescent material, but also shows excellent photovoltaic properties. Because its band can be continuously adjustable from 0.65eV to 3.4eV, it covers almost the whole visible spectrum, and also has high absorption coefficient, high mobility and high radiation resistance, so InGaN has great potential as a solar cell. The carrier transport of InGaN heterojunction solar cells is studied systematically in this paper. In the first chapter, the research progress of the application of InGaN materials in photovoltaic field, as well as the main problems and challenges are described. The simulation system used in this paper and the basic knowledge of heterojunction solar cells are also introduced. In chapter 2, the reason why the response wavelength of InGaN/Ga N multiple quantum well solar cells with different In components is far lower than the absorption edge is studied. We find that the carriers excited by low energy photons can reach a lower energy level and need to cross a very high barrier to escape the quantum wells. When the excited photon energy is below a certain threshold, the resulting carriers can only be recombined and have no contribution to the photocurrent. The photon energy threshold of carrier escape is related to the barrier thickness. The wavelength response limits of InGaN/Ga N multiple quantum well solar cells with different barrier thickness are calculated, which provides a reference for the design of InGaN/GaN multiple quantum well solar cells. In chapter 3, the role of V-type pits in In GaN multiple quantum well solar cells is studied. By means of numerical simulation, we find that V-type crater can provide carrier transport channel, which can improve the conversion efficiency. In addition, the V pits with different dislocation densities are discussed, and it is found that the more V pits are formed, the more obvious the lifting effect of the batteries is. In chapter 4, we study the effect of temperature on carrier transport in In GaN solar cells. We find that the temperature increases from room temperature to 360 K, and the increase of photocurrent increases with the increase of the injection current of the light source. This means that the total number of carriers escaping from quantum wells also increases. Our experimental results are well explained by quantum dot-quantum well composite model. In order to achieve higher efficiency, we optimize the heterojunction interface of InGaN p-i-n solar cells in Chapter 5. We find that using n-ZnO as the electron transport layer can not only improve the polarization effect caused by lattice mismatch. Moreover, the interface barrier can be reduced effectively, which is more favorable to the transport of photogenerated carriers. The conversion efficiency of p-type GaN can be improved from 7% to 14% by replacing p-type InGaN with photons absorbed and improving the properties of interface. Further optimization of the device size can improve the efficiency to 15. The sixth chapter summarizes the contents of the previous chapters and prospects for future applications.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM914.4
[Abstract]:With the wide use of blue LED materials, more and more attention has been paid to InGaN materials. It not only can be used as a luminescent material, but also shows excellent photovoltaic properties. Because its band can be continuously adjustable from 0.65eV to 3.4eV, it covers almost the whole visible spectrum, and also has high absorption coefficient, high mobility and high radiation resistance, so InGaN has great potential as a solar cell. The carrier transport of InGaN heterojunction solar cells is studied systematically in this paper. In the first chapter, the research progress of the application of InGaN materials in photovoltaic field, as well as the main problems and challenges are described. The simulation system used in this paper and the basic knowledge of heterojunction solar cells are also introduced. In chapter 2, the reason why the response wavelength of InGaN/Ga N multiple quantum well solar cells with different In components is far lower than the absorption edge is studied. We find that the carriers excited by low energy photons can reach a lower energy level and need to cross a very high barrier to escape the quantum wells. When the excited photon energy is below a certain threshold, the resulting carriers can only be recombined and have no contribution to the photocurrent. The photon energy threshold of carrier escape is related to the barrier thickness. The wavelength response limits of InGaN/Ga N multiple quantum well solar cells with different barrier thickness are calculated, which provides a reference for the design of InGaN/GaN multiple quantum well solar cells. In chapter 3, the role of V-type pits in In GaN multiple quantum well solar cells is studied. By means of numerical simulation, we find that V-type crater can provide carrier transport channel, which can improve the conversion efficiency. In addition, the V pits with different dislocation densities are discussed, and it is found that the more V pits are formed, the more obvious the lifting effect of the batteries is. In chapter 4, we study the effect of temperature on carrier transport in In GaN solar cells. We find that the temperature increases from room temperature to 360 K, and the increase of photocurrent increases with the increase of the injection current of the light source. This means that the total number of carriers escaping from quantum wells also increases. Our experimental results are well explained by quantum dot-quantum well composite model. In order to achieve higher efficiency, we optimize the heterojunction interface of InGaN p-i-n solar cells in Chapter 5. We find that using n-ZnO as the electron transport layer can not only improve the polarization effect caused by lattice mismatch. Moreover, the interface barrier can be reduced effectively, which is more favorable to the transport of photogenerated carriers. The conversion efficiency of p-type GaN can be improved from 7% to 14% by replacing p-type InGaN with photons absorbed and improving the properties of interface. Further optimization of the device size can improve the efficiency to 15. The sixth chapter summarizes the contents of the previous chapters and prospects for future applications.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM914.4
【参考文献】
相关期刊论文 前4条
1 江蓉;陆海;陈敦军;任芳芳;闫大为;张荣;郑有p，
本文编号：2203586
本文链接：https://www.wllwen.com/kejilunwen/dianlidianqilunwen/2203586.html
