指叉式背電極太陽能電池模擬分析及射極復合電流實驗分析

Abstract

本篇論文將著重在n型矽基板太陽能電池之射極特性的探討以及研究n型矽基板指叉式背電極太陽能電池的光電特性並藉由模擬，設計與優化太陽能電池。我們利用TCAD模擬軟體模擬新結構來探討有哪些因素會影響或增進太陽能電池之效率。 在第二章中主要探討n型指叉式背電極太陽能電池之二維模擬。藉由改變一些電性參數來探討如何影響電池效率，例如表面複合速度、少數載子生命週期以及射極的比例。此外，藉由模擬軟體模擬離子佈值製程的條件，並優化製程上設定的參數，例如離子佈值的劑量以及熱退火溫度。在第三章中，為了得到更高效率太陽能電池，結合了指叉式背電極太陽能電池以及異質接面太陽能電池的優點，稱之為指叉式背電極異質接面太陽能電池。此結構除了幾何結構會影響效率外，非晶矽的材料特性也會影響電池效率。我們利用TCAD 模擬軟體模擬幾何結構的設計以及非晶矽材料的能隙對效率的影響並進行優化。在第四章中則是探討n型太陽能電池之射極特性。藉由以離子佈值的方式做摻雜，製作一個p+/n/p+的對稱性結構並 進行量測，量測方法為準穩態光電導方法，由於離子佈值會在晶圓表面造成損害，若利用合適的熱退火條件以及優化過的濕蝕刻條件來製作射極，對提升太陽能電池的效率是有幫助的。

In this thesis, the characteristics of emitter of n-type Si-based solar cells are investigated and the enhancements of n-type Si-based interdigitated back contact (IBC) solar cells are also studied. The goals of this thesis are to optimize the parameter of solar cells by numerical simulations using technology computer aided design (TCAD) simulator to provide concepts to improve the performances of cells. Firstly, we vary the surface recombination velocity (SRV), the bulk lifetime and emitter ratio. Then, we simulate the process of the ion implantation by numerical simulators using TCAD simulator and optimize the parameter in the fabrication, such as the implanted dose and annealing temperature. Secondly, we combine the advantages of IBC solar cells and heterojunction with intrinsic thin films (HIT) solar cells to get the higher efficiency of solar cells, called interdigitated back contact silicon heterojunction (IBC-SHJ) solar cells. To optimize the efficiency, we simulate the design of the structure and the bandgap of p, i and n-type amorphous Si layers by using TCAD simulator. Finally, we discuss the characteristics in the emitter of n-type Si-based solar cells. A p+/n/p+ symmetrical structure is fabricated by ion implantation tool. We measure it to analyze the characteristics of the emitter by means of Quasi-Steady-State Photo-conductance (QSSPC) method. It is helpful to improve the efficiency of solar cells by using the appropriate annealing condition and the optimized wet chemically etching condition since the damage is introduced by ion implantation process.