High Optical Quality Polycrystalline Indium Phosphide Grown on Metal Substrates by MOCVD for Photovoltaic Applications

Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission. Figure 2: SEM top view and cross section, and TEM of grain boundaries and InP/Mo interface…………………………………………………………………………… 9 My broad research interests are in grid-level green energy generation and storage. Both of these are necessary for humanity's future. The need for green/renewable/sustainable energy is obvious, from either the peak oil or global warming arguments. But as the dominant technologies (wind, solar) are still vulnerable to the whims of nature, grid-level energy storage (MWh, GWh) is needed to change these from interruptibles to dispatchables and truly scale. These two, generation and storage, are inextricably linked going forward. My current research falls under the area of energy generation, and specifically III-V photovoltaics. Here, the goal is high-efficiency, low-cost terrestrial solar cells for electricity generation. As a commodity industry, cost is the most critical issue, and the metric used is dollars per watt. However, most fabrication, installation, and maintenance costs scale directly with area. In addition, for most projects, the area is fixed and so an equally important metric to consider is dollars per square meter. Hence, the true goal is to maximize power output for a given areal footprint, which is dictated by the power conversion efficiency. This is the reason there is a relentless focus on high-efficiency, and future solar cells will need to reach the 40-70% efficiency range to truly become ubiquitous. III-Vs are a natural choice to achieve this goal. They have the highest demonstrated efficiencies for single-junction solar cells. They span a large range of band gaps, and can be combined in multi-junction cells to cover nearly the entire solar spectrum. The large absorption coefficients also dictate minimal use of material. However, the complex and costly processing schemes have been a large enough disadvantage to limit them mainly to space applications. My goal is to explore low-cost manufacturing processes for producing III-V solar cells, both single-and multi-junction. Along these lines, this project, " High Optical Quality 4 Polycrystalline Indium Phosphide Grown on Metal Substrates by MOCVD " is an effort to …