Investigations of LPCVD-ZnO front contact TCO on large area for amorphous silicon solar cell applications

The present paper will give insight into amorphous silicon based photovoltaic thin film technology with a special focus on implementing LPCVD ZnO front contact. ersol Thin Film GmbH (ETF) evaluated amorphous silicon modules on growth-textured Zinc Oxide (ZnO) films. The process is based on substrate glasses with outer dimensions of 1100 × 1300 mm². The use of growth-textured Zinc Oxide layers for an enhanced light-trapping in amorphous silicon solar cells has been continuously developed in recent years and has been successfully implemented already (1), but no module fabrication started at this time. ETF currently evaluates buy or built concepts for the front contact and benchmarks in this context home-made´ TCO layers against purchased TCOs. This paper will report on experience made in the environment of the newly erected 40 MWp facility in Erfurt (Germany). Key issues are related to the integration of the newly developed LPCVD ZnO:B into the module process (2,3). We will report on key film properties e.g sheet resistance, uniformity and haze achieved during the experiments and will comment on the correlation to electrical parameters.