Amorphous silicon solar cells made with SnO2:F TCO films deposited by atmospheric pressure CVD

In this paper we report the results of a study assessing a newly developed deposition process for F-doped SnO2 films by CVD operating at atmospheric pressure (APCVD). The technology is designed to be compatible with industrial requirements such as high process speed, possible up-scaling to wide substrate widths and low costs. The optical and electrical properties of layers deposited on glass are found to be similar to those of commercially available low pressure CVD. Optical absorptance below 1% is achieved for films of around 0.8 μm thick. Such transparent conductive oxide (TCO) is used with a-Si:H single junction p–i–n solar cells grown by PECVD. The cells are characterised by I–V measurements using AM1.5 spectra and by measuring the external quantum efficiencies (EQE). The initial efficiencies were up to 9.3% with FF = 73%. The TCO films demonstrated an enhanced performance in the EQE compared to commercially available TCO (Asahi-U).