Modeling and simulation of a dual-junction CIGS solar cell using Silvaco ATLAS

Abstract

The potential of designing a dual-junction Copper Indium Gallium Selenide (CIGS) photovoltaic cell is investigated in this thesis. Research into implementing a dual-junction solar cell, using a CIGS bottom cell and different thin-film designs as a top cell, was conducted in order to increase the current record efficiency of 20.3% for a single CIGS cell. This was accomplished through modeling and simulation using Silvaco ATLASTM, an advanced virtual wafer-fabrication tool. A Silvaco ATLASTM model of a single CIGS cell was created by utilizing actual solar cell parameters (such as layer thicknesses, gallium ratio, doping levels and materials properties) documented in different papers, and work from previous NPS theses provided the background for modeling with Silvaco ATLASTM. After the individual CIGS solar cells were built, a dual-junction cell was created by adding the layers of another CIGS solar cell whose parameters (layers thicknesses, Ga ratio) were varied to produce an optimum efficiency of 24%. This approach is promising to produce a multi-junction CIGS cell with record efficiency.