Formation of MoOx barrier layer under atmospheric based condition to control MoSe2 formation in CIGS thin film solar cell

ABSTRACTAs part of the device fabrication process, selenization step is required to crystallise the CIGS absorber layer. However, during high temperature selenization process, excessive formation of MoSe2 can lead to delamination of the film and adverse effect on electrical properties of the solar cells. In this paper, a new method is proposed to form a Molybdenum Oxide (MoOx) barrier layer in between of the Mo back contact using plasma jet under atmospheric based conditions. The effect of MoOx compound (MoO2 and MoO3) towards the efficiency of the device is investigated. It has been proven that a thin layer of MoOx barrier layer is able to control the formation of MoSe2 effectively and provide a significant improvement in electrical properties of the devices. A power conversion efficiency of 5.24% with least efficiency variation across the champion device was achieved which demonstrates the importance of this methodology on small area devices.