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

Abstract

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 (/spl les/300/spl deg/C) to control the solidification velocity, grain sizes up to 0.445 /spl mu/m have been achieved, with an area weighted average up to 0.243 /spl mu/m. These grain sizes, which are comparable to reports using excimer lasers on much thinner films, were achieved on 1 /spl mu/m thick PECVD a-Si on quartz substrates making them potentially of interest for photovoltaic devices. Crystallinity was characterised using FESEM and Raman measurements.