A catalyst which is able to express a high oligomerizing activity of ethylene and a method for the production of -olefin where ethylene is oligomerized using said catalyst are provided. In various exemplary embodiments, the raised structure may comprise two forward extending ridges located near the edges of the snowboard. The gate electrode is embedded by fusing the organic semiconductor layer. The invention thus provides a dirt-resistant valve, which is easy to operate, has fixed valve members and does not require additional equipment.