Abstract: Provided at low cost is a multi-quantum well solar cell such that recombination of carriers generated by light absorption is suppressed and a high photoelectric conversion efficiency is achieved. This multi-quantum well solar cell comprises a substrate, a p-type semiconductor layer, a barrier layer, a well layer, an n-type semiconductor layer, and electrodes, and is characterized in that the barrier layer and the well layer comprise crystals having a wurtzite crystal structure, the well layer is composed of a metal-oxynitride that comprises Zn and at least one element selected from a group consisting of In, Ga, and Al, and a piezoelectric electric field is generated in the well layer. This allows for the provision of a multi-quantum well solar cell such that recombination of carriers generated by light absorption is suppressed and a high photoelectric conversion efficiency is achieved.

Abstract: An apparatus for processing particulate dust when a substrate is arranged in a high vacuum enclosure, plasma is generated in the high vacuum enclosure, and a reactive material is introduced into the high vacuum enclosure to perform processing of the substrate. At least one collecting electrode is provided around the substrate in the high vacuum enclosure other than the electrode that generates plasma, and particulates generated in plasma are efficiently removed by applying a predetermined electric potential of a direct-current or an alternating current to the collecting electrode, and thus a deposition problem onto an inner wall of the vacuum enclosure and a deterioration problem of processing accuracy and a film quality associated with flowing of the particulates onto the substrate are solved.