Tham khảo tài liệu 'solar energy 2012 part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 15 Amorphous Silicon Carbide Photoelectrode for Hydrogen Production from Water using Sunlight Feng Zhu1 Jian Hu1 Ilvydas Matulionis1 Todd Deutsch2 Nicolas Gaillard3 Eric Miller3 and Arun Madan1 1MVSystems Inc. 500 Corporate Circle Suite L Golden CO 80401 2Hawaii Natural Energy Institute HNEI University of Hawaii at Manoa Honolulu HI 96822 3National Renewable Energy Laboratory NREL Golden CO 80401 USA 1. Introduction Hydrogen is emerging as an alternative energy carrier to fossil fuels. There are many advantages of hydrogen as a universal energy medium. For example it is non-toxic and its combustion with oxygen results in the formation of water to release energy. In this chapter we discuss the solar to hydrogen production directly from water using a photoelectrochemical PEC cell in particular we use amorphous silicon carbide a-SiC H as a photoelectrode integrated with a-Si tandem photovoltaic PV cell. High quality a-SiC H thin film with bandgap was fabricated by plasma enhanced chemical vapor deposition PECVD technique using SiH4 H2 and CH4 gas mixture. Incorporation of carbon in the a-SiH film not only increased the bandgap but also led to improved corrosion resistance to an aqueous electrolyte. Adding H2 during the fabrication of a-SiC H material could lead to a decrease of the density of states DOS in the film. Immersing the a-SiC H p a-SiC H i structure in an aqueous electrolyte showed excellent durability up to 100 hours so far tested in addition the photocurrent increased and its onset shifted anodically after 100-hour durability test. It was also found that a SiOx layer formed on the surface of a-SiC H when exposed to air led to a decrease in the photocurrent and its onset shifted cathodically by removing the SiOx layer the photocurrent increased and its onset was driven anodically. Integrating with a-Si H tandem cell the flat-band potential of the PV a-SiC H structure shifts significantly below the H2O O2 half-reaction potential and is in an .
