The third-generation solar cell technologies are aiming to achieve substantially higher efficiency over the Shockley-Queisser limit of a single junction solar cell while maintaining low fabrication cost per area in order to become cost competitive with coal fuel. The demanding of a breakthrough in efficiency leads the research to the development of photovoltaic devices with a new concept of fundamental operation other than the structure of single junction solar cells and to the employment of various materials and nanostructures to the devices. The purpose of the projects in this book to present nanostructures with type-II heterointerface that can provide additional possibilities to certain types of third generation solar cells for achieving an efficiency close to the theoretical maximum limit.