Laser crystallisation of a-Si using copper vapour lasers: a different option for photovoltaic applications

The copper vapour laser (CVL) provides a pathway to relax some of the sample restrictions encountered by excimer lasers, and allow reapplication of the techniques developed for excimer lasers. Using a CVL focused spot, combined with low temperature substrate heating (⩽300°C) to control the solidification velocity, grain sizes up to 0.445 μm have been achieved, with an area weighted average up to 0.243 μm. These grain sizes, which are comparable to reports using excimer lasers on much thinner films, were achieved on 1 μm thick PECVD a-Si on quartz substrates making them potentially of interest for photovoltaic devices. Crystallinity was characterised using FESEM and Raman measurements