EAGER: III-Nitride Solar Cells

Non-technical:

There are currently several approaches to improve the cost of photovoltaic (PV) devices in terms of dollars per watt ($/W). Silicon solar cells, the most common device structures, are approaching theoretical limits of both performance and efficiency. The most promising approach to drive down the cost of solar energy is the use of multi-junction solar cells (MJSCs) due to their efficient use of the solar spectrum. Solar cells made from indium gallium nitride (InGaN) can have a huge impact on the technology and understanding of the basic properties of photovoltaic devices. The portion of the solar spectrum that an InGaN alloy absorbs can be tuned by varying the relative fraction of indium and gallium. The development of InGaN to a larger range of compositions will lead to wider applications of III-Nitrides as solar cells. The ability to use one material system made of very thin InGaN layers, grown on cheap sapphire substrates for the integrations of MJSCs will reduce the cell manufacturing cost. By improving the overall MJSC efficiency and incorporating them into solar panel production, the cost per watt of individual panels, and thus the total system cost will be reduced. The aim of this EAGER project is to explore and develop In(x)Ga(1-x)N-based solar cell structures that absorb a larger portion of the solar spectrum with efficiency that is comparable to the current III-V compound cells. Both single and multi-junction solar cells will be explored.

Technical:

This EAGER project focuses on the development of solar cells based on InGaN material system to achieve high efficiency III-Nitrides solar cells, single junction and multi-junction solar cells. The aim is to develop InxGa1-xN-based solar cells that absorb a larger portion of the solar spectrum with efficiency that is comparable to the current III-V compound structures. Both single and multi-junction solar cells will be explored and developed. The project will investigate methods to achieve this goal including: 1. Utilizing InxGa1-xN films with high In-content, x up to 45%. 2. Develop solar cells with several hundred nanometers of InxGa1-xN to fully absorb the incident radiation. The research will train one graduate student at North Carolina State University to acquire interdisciplinary research experience and become an expert in the field of alternative energy and solar cell technology.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.