Porous germanium Efficient Epitaxial LayEr Release (PEELER) for low cost high performance III-V solar cells

清洁、可再生和廉价的能源不仅是本世纪最重要的挑战，而且很可能是发达国家最大的金融机遇之一。与目前的化石燃料经济相反，即将到来的清洁能源市场的赢家将不是那些拥有资源的国家，而是那些控制技术的国家。光伏发电预计将在这个新兴市场中发挥重要作用，但如果这项技术要达到能够大规模采用的特点，必须克服几个障碍，例如提高能源转换效率、生产和安装成本。该项目旨在解决这些障碍的核心技术挑战——高效光伏（PV）太阳能电池的材料成本。基于硅的光伏电池已经成熟了好几年，其成本也在下降，但其最大效率仍在20%左右。幸运的是，该团队中的加拿大研究人员使用先进的III-V半导体结构实现了42%或更高的电池效率，这些结构来自他们最近在电信组件技术方面的领先地位。尽管由这些材料制成的多结电池比硅电池更昂贵，但它们能够在非常高的照明水平下工作，并且在相同的照明下产生比硅电池更多的千瓦时能量。利用这一特性，太阳能系统开发人员设计了可移动的透镜系统，以跟踪和聚焦太阳光线到高效电池的小区域，从而减少所需的材料。为了进一步降低材料成本负担，该项目将展示如何使用特殊制备的锗（Ge）衬底来生长必要的太阳能电池层，然后将其从衬底上移除并安装在低成本的散热器上，从而释放锗衬底以再次使用。这些电池的净成本节约和电力输出的增加创造了一个成功的组合，将进一步激励加拿大和全球家庭和企业部署太阳能，这样做将有助于保护环境。

Clean, renewable and inexpensive energy is not only this century's most important challenge, but also it is most likely one of the largest financial opportunities for developed countries. Contrary to the current fossil fuel economy, the winners of the upcoming clean energy market will not be the ones possessing the resource, however it would be rather the ones controlling the technology. Photovoltaic generation of electricity is expected to play a major role in this emerging market, but several hurdles must be overcome if this technology is to reach the characteristics that will enable massive adoption, such as improved energy conversion efficiency, production and installation costs. This project aims to address a technology challenge that lies at the heart of these hurdles - the cost of the materials for high-efficiency photovoltaic (PV) solar cells. PV cells based on silicon have been maturing for a number of years and their cost is falling, but their maximum efficiency remains at about 20%. Fortunately, the Canadian researchers in this team have achieved cell efficiencies of 42% or more using advanced III-V semiconductor structures that emerged from their recent leadership in telecommunications component technology. Even though the multi-junction cells made from these materials are more expensive than silicon cells, they are able to function at very high levels of illumination and produce more kWh of energy for the same illumination as a silicon cell. Taking advantage of this property, solar system developers have engineered movable lensing systems to track and focus the sun's rays onto small areas of the highly-efficient cells, so that less of the material is needed. To further reduce the material cost burden this project will demonstrate how specially-prepared germanium (Ge) substrates can be used to grow the necessary solar cell layers, which are then removed from the substrate and mounted on a low-cost heat-sink, thereby freeing the Ge substrate to be used again. The net cost savings and increased electrical output of these cells create a winning combination that will further motivate the deployment of solar power for homes and businesses in Canada and globally, and in so doing will help to preserve the environment.