Use of Induction Heating As An Inexpensive Process to Dramatically Improve the Structure and Grain Size of Compound Semiconductor Absorber Layers for Photovoltaic Applications

The performance of thin-film photovoltaic devices is highly dependent on the microstructural quality of the absorber layer. The high defect densities characteristic of Cu(In,Ga)Se₂ (CIGS) and Cu₂ZnSn(S,Se)₄ (CZTSSe) thin-films lead to reductions in the minority carrier lifetime, mobility and even the optical absorption of the resulting material. This has led to the development of controlled growth methods to produce dense thin-film absorber layers exhibiting large, highly-crystalline grains. However, these processes are typically expensive, increasing the ever-important performance metric, cost per watt. Here, we report the use of induction heating under an applied pressure as an inexpensive, novel process for the synthesis of high quality semiconductor thin-films from particulate precursor materials. The process has been applied to CIGS, CZTSSe and other complex chalcogenide absorber layers.