Fabrication Of Silicon Nanowire Solar Cells And Research On Minority Carriers' Recombination Mechanism

Clean, renewable and climate suitable energy resources have been paid much attention. Photovoltaic technologies are booming into a huge market with relatively mature technologies and industrial level. Solar cells are the basic generating units and the core of PV systems. The efficiency and performance of such cells decide the performance and the cost of the systems. As the most widely utilized technology, traditional planar silicon based solar cell technology has its own limits. In order to improve the performance, silicon nanowire structure, which has better electrical and optical properties, can take the place of planar silicon structure.There are two research topics in our work. Firstly, silicon nanowires(SiNWs) were fabricated by metal assisted chemical etching method(MACE). To fabricate the SiNW based solar cells, we first used plasma enhanced chemical vapor deposition(PECVD) to form the heterojunction intrinsic thin layer(HIT) structure and to make p-n junction. Then we used the sputtering system to deposit ITO layer on the samples. As for the metal contacts, we use the e-beam evaporation system to deposit aluminum on the samples. Secondly, minority excess carriers' recombination mechanism was measured by time-resolved microwave conductivity(TRMC) in our work, which is significant in regard of efficiency and performance of the solar cells. From TRMC signals, we induced the carriers' recombination mechanism in silicon nanowire materials. The passivation effectiveness was investigated. In addition, we performed LabVIEW and MATLAB to deal with the data.There are five chapters in all. In Chapter 1, the basic information about world's energy use situation, solar cells, silicon nanowires and carriers' recombination mechanism will be introduced. In Chapter 2, the fabrication of SiNWs and SiNW based solar cells will be discussed. In Chapter 3, the principle and the equipment of TRMC measurement will be presented and discussed. In Chapter 4, analysis of TRMC signals and deduction of the physics models under various wavelengths illumination will be performed. In Chapter 5, there will be the discussion and conclusion of this thesis and expectations of the future work.