GaAs/In(0.5)Ga(0.5)P 雙接面太陽能電池磊晶與製程的設計

Abstract

In recent years, due to the shortage in energy supply, the development of alternative energy has caught great attention. Moreover, since solar energy is huge energy supply source and produces very low environmental contamination, it is thus very good alternative energy, and it thus has caught attention and is under wide research. The multi-junction Ⅲ-Ⅴ solar cell studied in this experiment has pretty high energy conversion efficiency, which is a pretty good research direction. Since multi-junction solar cell is serially connected by semiconductor materials of different energy gaps, the current of the entire device is thus limited by the smallest current in each part of the cell. Therefore, the enhancement of smallest current value and the reach of current match is a very important topic for the enhancement of conversion efficiency. In the experiment, PC1D and APSYS simulation software is used first for the simulation of GaAs and InGaP single junction solar cell structure and GaAs / InGaP double junction solar cell structure. Through the simulation process, the results of the influence of the material type, thin film thickness and doping concentration on conversion efficiency were obtained, and the structure optimization objectives were then obtained. Then Metal organic chemical vapor deposition ( MOCVD ) method is used to grow Ⅲ-Ⅴ solar cell structure, which includes GaAs and InGaP single junction solar cell structure and GaAs / InGaP double junction solar cell structure. Here, we found that the quality of the thin film material formed is mainly due to the internal flow field stability in the reactor chamber, temperature control, temperature uniformity, and the reaction situation of the reaction gas, etc. Therefore, the controllable crystal growth parameters are the key points to be investigated regarding the thin film quality, and the parameter are, for example, temperature, crystal growth rate, reactor pressure, Ⅴ-Ⅲ ratio, lattice constant, and substrate selection, etc. In the first chapter of this thesis, an overview will first be done on the development history of the solar cell, then the development advantages of Ⅲ-Ⅴ solar cell and the research direction of this experiment will be described. In chapter 2, we are going to introduce the work principle, equivalent circuit and basic parameters of solar cell, then it will be introduction of the basic structure of compound semiconductor solar cell. Chapter 3 will be introduction of the simulation result of GaAs, InGaP single junction solar cell and GaAs/InGaP double junction solar cell as performed by PC1D and APSYS simulation software. Wherein it includes the physical parameter setup as needed in the simulation and the planning of solar cell structure. Chapter 4 will be introduction of the principle and system of MOCVD, which includes MOCVD reactant characteristics, epitaxial parameter consideration and setup, and the introduction and description of the measurement equipment for epitaxial thin film. Finally, in chapter 5, it will be an extension of the study in chapter 3 and 4. It will use MOCVD to grow GaAs、 InGaP single junction solar cell and GaAs/InGaP double junction solar cell. Moreover, analysis and discussion will be performed on the measurement result, and finally, a complete conclusion and the future work will be presented for chapter 6.