High-throughput Processes for Industrially Scalable Deposition of Zinc Oxide at Atmospheric Pressure

ZnO films have been grown on a moving glass substrate by high temperature (480 0C) chemical vapour deposition (CVD) and low temperature (200 0C) plasma enhanced CVD (PE-CVD) process at atmospheric pressure. Deposition rates above 7 nm/s have been achieved for substrate speeds from 20 to 500 mm/min. The conductivity of the films is enhanced by Al doping of CVD ZnO or by exposure to near-UV radiation of PE-CVD ZnO. Both CVD ZnO:Al and UV-exposed PE-CVD i-ZnO films are highly transparent (> 85% in the visible range) and conductive (< 15 Ohm/sq for a thickness above 1200 nm). ZnO:Al has been used as front electrode in amorphous silicon (a-Si:H) solar cells while i-ZnO has been applied as electrode in CIGS solar cells, achieving an efficiency of 8% and 15.4%, respectively.