Impact of carrier lifetime on efficiency of photolytic hydrogen generation by p-type SiC

三宅 景子*; 安田 智成*; 加藤 正史*; 市村 正也*; 畑山 智亮*; 大島 武

Materials Science Forum, 778-780, p.503 - 506, 2014/02

Photolytic hydrogen generation using sunlight is regarded as energy production technology for the next generation. One of the key of issues for this technology is a selection of materials for the photolysis. Silicon carbide (SiC) is expected as one of the candidate materials for this application. In this study, we measured carrier lifetimes in SiC by the microwave photoconductivity decay (PCD) method. In order to control carrier lifetime in SiC, some samples were irradiated with 160 keV-electrons with fluences between 110 and 110 /cm. The values of carrier lifetime in SiC were compared to photocurrents in electrolytes which directly relate to the conversion efficiency of photolytic hydrogen generation. As a result, photocurrents depend on the sum of the depletion layer width and the diffusion length which was estimated from carrier lifetimes.